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CABD Seminar 27 November


Friday 27 Nov. @ 12 NEXT WEEK
(To view this week's seminar information visit our webpage)


CABD Seminar 27 November

Transcriptional networks in haematopoiesis


Dr. Diego Miranda-Saavedra

Cambridge Institute for Medical Research
Wellcome Trust/MRC Building
Cambridge, UK

Haematopoiesis is the process whereby haematopoietic stem cells (HSC) give rise to the array of fully differentiated blood cells.  As in other developmental systems, the haematopoietic process is characterised by a progressive restriction in developmental potential and an associated lineage commitment.  These are brought about by specific genetic networks.  In this talk I will first of all provide a brief overview of the key transcription factors (TF) known to be essential for HSC identity.  Next, I will introduce the BloodExpress database, an integrated collection of expression profiles in mouse haematopoiesis.  The integration of expression data with new post-genomic tools, such as ChIP-sequencing, is revolutionising our ability to map TF binding sites and therefore reconstruct gene regulatory networks.  A main part of the seminar will involve the ChIP-sequencing of the very important Scl/Tal1 TF and how this has been integrated with expression data from the BloodExpress database and with further bioinformatic analyses to extend the knowledge of the transcriptional networks controlled by this TF.  In the final part of the seminar I will introduce a novel bioinformatic method for comparing the microarray expression data of haematopoietic cells that have been profiled on different platforms.  The method works by implementing a sophisticated statistical model of multivariate regression that allows the inference of specific TF activities.  This has been followed by the development of a classifier of cell types based on calculated TF activities.  This classifier is useful for placing developmentally abnormal cell types in the haematopoietic hierarchy by their TF activities and thus rationalise at the same time the underlying abnormal genetic networks.

References
1) Miranda-Saavedra, D. et al  (2009) BloodExpress: a database of gene expression in mouse haematopoiesis.  Nucleic Acids Research vol. 37(Database Issue): D873-9.
2) Wilson, N.K., Miranda-Saavedra, D.,  et al (2009) The transcriptional programme controlled by the stem cell leukaemia gene Scl/Tal1 during early embryonic haematopoietic development.  Blood 113(22): 5456-65.

Host: María José Sánchez
newsletter sent on 18/11/2009
CABD Seminar 27 November is at 10am!


Change to this Friday's seminar schedule due to a thesis defence


 This Friday's seminar will be at 10 a.m.

Friday 27 Nov. @ 10 a.m.


CABD Seminar 27 November

Transcriptional networks in haematopoiesis


Dr. Diego Miranda-Saavedra

Cambridge Institute for Medical Research
Wellcome Trust/MRC Building
Cambridge, UK

Haematopoiesis is the process whereby haematopoietic stem cells (HSC) give rise to the array of fully differentiated blood cells.  As in other developmental systems, the haematopoietic process is characterised by a progressive restriction in developmental potential and an associated lineage commitment.  These are brought about by specific genetic networks.  In this talk I will first of all provide a brief overview of the key transcription factors (TF) known to be essential for HSC identity.  Next, I will introduce the BloodExpress database, an integrated collection of expression profiles in mouse haematopoiesis.  The integration of expression data with new post-genomic tools, such as ChIP-sequencing, is revolutionising our ability to map TF binding sites and therefore reconstruct gene regulatory networks.  A main part of the seminar will involve the ChIP-sequencing of the very important Scl/Tal1 TF and how this has been integrated with expression data from the BloodExpress database and with further bioinformatic analyses to extend the knowledge of the transcriptional networks controlled by this TF.  In the final part of the seminar I will introduce a novel bioinformatic method for comparing the microarray expression data of haematopoietic cells that have been profiled on different platforms.  The method works by implementing a sophisticated statistical model of multivariate regression that allows the inference of specific TF activities.  This has been followed by the development of a classifier of cell types based on calculated TF activities.  This classifier is useful for placing developmentally abnormal cell types in the haematopoietic hierarchy by their TF activities and thus rationalise at the same time the underlying abnormal genetic networks.

References
1) Miranda-Saavedra, D. et al  (2009) BloodExpress: a database of gene expression in mouse haematopoiesis.  Nucleic Acids Research vol. 37(Database Issue): D873-9.
2) Wilson, N.K., Miranda-Saavedra, D.,  et al (2009) The transcriptional programme controlled by the stem cell leukaemia gene Scl/Tal1 during early embryonic haematopoietic development.  Blood 113(22): 5456-65.

Host: María José Sánchez

newsletter sent on 23/11/2009
CABD Seminar 20 Nov
Friday, November 20th, @ 12:00
 

Dr. Alfonso Martínez Arias

"Origin, function and regulation of nongenetic heterogeneities in development"

Dept of Genetics, Univ of Cambridge, UK.

Summary: Genetically homogeneous populations can exhibit differences in profiles of gene expression which, until recently, have been ignored. Recent studies, particularly in embryonic stem (ES) cells have revealed that genes involved in pluripotency exhibit these such heterogeneities. Furthermore these heterogeneities are a hallmark of pluripotency. Using a GFP reporter for Nanog, a key pluripotency marker, we show that these heterogeneities have dynamic properties that can be captured by an excitable noise driven dynamical system with Nanog at its center. In this talk I shall discuss the implications of these observations for the the process of cell fate assignation in development.

Host: Lola Martín Bermudo

newsletter sent on 17/11/2009
CABD Seminar 13 Nov
CABD Seminar

Friday, November 13th, @ 12:00
 

Dr. Cornelia Fritsch

"Functional evolution of a recently duplicated Bone Morphogenic Protein in Drosophila"

Dpt. Biochemistry, University of Sussex, UK.

Summary: The main Drosophila Bone Morphogenic Protein (BMP) type morphogen is Decapentaplegic (Dpp), which is the orthologue of vertebrate Bmp-2/4. Dpp signalling is modulated by two other BMPs: the Bmp-5/6/7/8 orthologue Glass bottom boat (Gbb), and Screw (Scw), which does not appear to have a direct vertebrate counterpart. We have studied the functional and evolutionary relationship of Gbb and Scw and found that Scw originated from a duplication of Gbb in the lineage leading to higher Diptera. After the duplication scw has acquired a novel function and the Scw protein sequence has changed significantly while Gbb retained its ancestral sequence and functions. In addition, other components of the BMP signalling pathway have been duplicated in higher Diptera with one copy functioning along with Scw and the other copy modulating Gbb signalling. However, our studies suggest that the main difference between Gbb and Scw signalling is due to the fact that these two ligands have acquired distinct receptor specificities. BMPs are expressed as precursor proteins that are cleaved by subtisilin like pro-protein convertases. Gbb and Scw contain several potential cleavage sites. Our functional studies revealed that although the main sites are conserved between Gbb and Scw, deleting them has different consequences on the signalling ability of these two closely related proteins.


newsletter sent on 10/11/2009
Reminder Today's Ectopic seminar at 12
TODAY!!!!!

Tuesday, October 27th, @ 12:00

 

Dr Peter Holland

"Homeobox genes, genomes and animal evolution"

Department of Zoology, Oxford University, UK.

 

Summary:

The homeobox genes are a very diverse gene family, with over 200 members in vertebrate genomes and more than 100 in most invertebrates. These include many well known and highly conserved genes with roles in embryonic development, such as the Hox, ParaHox, Evx, Gsc, NK, and others. However, the excitement surrounding similarities between species has masked some dramatic differences. I will outline how gene family and genome comparisons have revealed unexpected cases of fast-evolving homeobox genes, not conserved between distant species, plus dramatic cases of homeobox gene duplication and gene loss. The challenge now is to relate changes in gene repertoire to evolutionary changes in the development of animals.

newsletter sent on 27/10/2009
CABD Seminar 29 Sept
Tuesday, September 29th,

Today! @ 12:00


Synaptic Homeostasis and Sleep in Drosophila
Dr. Giorgio F. Gilestro
Department of Psychiatry, University of Wisconsin, Madison, USA

SUMMARY Sleep is a universally conserved  behavior whose function still remains elusive. Our lab recently proposed a model for sleep function that links sleep need to the homeostatic regulation of synaptic strength, in a mutual bi-directional fashion. Using Drosophila as model system, we analyzed both directions of this connection.
            Using two different molecular markers of synapse number (the structural proteins BRP and DLG) and three markers of synaptic function (the components of vesicle secretion machinery: SYN,  SYX, CSP) we investigated how sleep and wakefulness affect the dynamic regulation of bona fide  synaptic strength in the Drosophila brain. We found that prolonged wakefulness induces a diffuse increase in synaptic number/volume, while restorative sleep has the opposite effect. Using two different paradigms of sleep deprivation we showed that the increase is specific to and correlate with the amount of time the flies spend being awake. Conversely, sleep-induced decrease in synaptic markers is proportional to the amount of time flies spend asleep and it is independent from circadian entrainment. Using confocal imaging, we showed that the increase in the expression of synaptic markers is widespread across the entire brain and that it correlated with a volumetric increase in specific area of the brain involved in learning.
            To manipulate synaptic function and strength, we ectopically expressed genes known to increase or decrease synaptic activity in vivo. We showed that a widespread increase in synaptic number in the Drosophila brain induces an increase in sleep drive and that, conversely, a decrease in synaptic number is followed by a decrease in sleep time. In particular, manipulation of synaptic activity (whether pan-neuronally or in specific area of the brain) affects length of sleep time, quality of sleep and recovery after sleep deprivation.
            In conclusion,  our results suggest that, in flies, sleep regulates synaptic strength dynamics and synaptic strength regulates sleep need.
          
newsletter sent on 29/09/2009
CABD Seminar 18 Sept
 Sept 18, 12:00

Regulation of intracellular transport by small GTPases
Professor Anne Spang
Biozentrum, University of Basel
Switzerland

Various small GTPases of the ras superfamily play a pivotal role in the intracellular communication and in the maintenance of organellar identity. GTPases of the rab family are key in providing organellar identity which is best studied in the endosomal system. We use the roundworm C. elegans to study membrane dynamics and their regulation in the context of a whole animal. The small rab-GTPase RAB-7 acts in endosome and endosome to lysosome traffic. We identified SAND-1 as a protein required for RAB-7 function based on similarities between SAND-1 and RAB-7 RNAi phenotypes. While the initial uptake of yolk protein in oocytes, or of secreted soluble (ss) GFP in coelomocytes, appeared normal, further transport along the endocytic traffic route was delayed in the absence of SAND-1 function, and yolk proteins failed to reach yolk granules efficiently. Moreover, in coelomocytes ssGFP and BSA-Texas-Red were endocytosed but not transported to lysosomes. We show that SAND-1 is essential for RAB-7 function at the transition from early to late endosomes, but not for RAB-7 function at the lysosomes. I will discuss how SAND-1 specifically affects RAB-7 and the upstream acting GTPase RAB-5.

Host: Peter Askjaer
newsletter sent on 10/09/2009
Extra!!!! CABD Seminar at 10:30
Please NOTE!!!
This seminar is at 10:30 not to clash with Anne Sprang's seminar at noon.


The role of Rap1 signaling in adherens junction homeostasis and epithelial cell sorting processes

Dr Benjamin Boettner,  
Cold Spring Harbor Laboratory, USA

The role of Rap1 signaling in adherens junction homeostasis and epithelial cell sorting processes
The morphogenesis of epithethelial tissues critically relies on the coherence of their constituent cells.  Intercellular coherence is brought about by adherens junctions (AJs) that have to be continuously maintained and during growth periods likely require extensive remodeling between sister cells in the late stages of cytokinesis.  In many expanding epithelia cohesion between sister cells emerging from cell division is fixed and perpetuated, which results in mitotic lineages that mostly display compact geometries within the tissue.  Deficiency of the small Rap1 GTPase encoding gene has been associated with a failure to properly remodel AJs in late cytokinesis.  In the model epithelium of the Drosophila wing imaginal disc Rap1 mutant cells loose cohesion and start to intermingle with and invade into non-mutant tissue.  Concomitantly, proper positional allocation and the compact appearance of mitotic lineages are significantly disrupted.  I will discuss effector functions of Rap1 in this process and will particularly focus on the multi-domain adaptor Canoe, a Drosophila homologue of the mammalian AF-6 and Afadin proteins, which have been involved in adherens junction biology and oncogenic processes.  Our analysis allows us to start explain the relationship of Rap1/Canoe signaling to other regulators of AJs, which I will discuss in the context of the ‘Differential Adhesion Hypothesis’.
newsletter sent on 10/09/2009
Next CABD Seminar Florenci Serras

Tomorrow!

Friday, July 3rd, @ 12

 

Dr. Florenci Serras

Exploring the Cellular Basis of Imaginal Disc Regeneration

Dept Genètica, Universitat de Barcelona

 

Summary: Regeneration is the ability of an organism to rebuild a part of its body that has been damaged or completely amputated. This phenomenon has fascinated scientists throughout the history of science, but it was two centuries ago when naturalists were captivated by animal regeneration and performed some systematic approaches that ended placing regeneration research in the nascent modern experimental biology. It is since long considered that regeneration studies cover a wide scope of phenomena with a variety of grades ranging from tissues that just heal the wound after injury to organs that can completely regenerate. But the most intriguing aspect of tissue regeneration is the capacity to recapitulate the developmental cues set during development in order to reconstruct lost tissues or organs. This clearly links regeneration to pattern formation. Actually, it opens the question of how developmental strategies used for developing an organ are re-used for regeneration.

Drosophila melanogaster has become a model for the study of pattern formation. Moreover, Drosophila makes an ideal organism to study genetics of regeneration. In addition, it is relatively complex compared to other genetic model systems, and uses many developmental features that resemble our own. The advances in molecular biology, genetic engineering and genetic analysis applied to Drosophila research, has uncovered some of the most relevant processes of pattern formation and morphogenesis. This has been particularly significant for studies on the imaginal discs, which are epithelial sacs of the larvae that contribute to adult structures such as legs, wings, eyes, antennae, head capsule, halteres and genital organs.

The aim of this seminar is to summarize our knowledge on imaginal disc regeneration, mainly the wing disc, and put it together with some new advances in order to present Drosophila imaginal discs as emerging model to study the cellular, genetic and molecular basis of regeneration.
newsletter sent on 02/07/2009
Next CABD Seminar Sofia Araujo


Friday, June 26th, @ 12



Shared molecules involved in neural and tracheal morphogenesis in Drosophila melanogaster.

Dr. Sofia J Araújo

IRB Barcelona, Institut de Biologia Molecular de Barcelona (CSIC), Parc Cientific de Barcelona.

Summary. "Cellular migration and pathfinding are two processes essential to tissue morphogenesis in the development of all multicellular organisms. In Drosophila melanogaster both neural and tracheal morphogenesis involve these complex mechanisms. Tracheal branches and nerves are intricate structures that share a high degree of anatomical similarity and their guidance has to be highly regulated in order to ensure proper targetting. To date, studies into the development of Drosophila’s nervous and tracheal systems have been often performed separately, despite the many common features within the two systems. It is likely that there are not only shared mechanisms, but also cellular cooperation between the two developing systems.
Common features between nervous and tracheal systems have already been demonstrated at the level of the guidance of tracheal terminal branches. Ganglionic branches, as they approach the CNS of Drosophila, are guided by some of the same molecules involved in axonal pathfinding. Robo and its ligand Slit have been shown to take part in ganglionic branch pathfinding and Vilse is involved in mediating Robo repulsion in tracheal cells and axons.
To study interactions we have been analysing Drosophila EMS mutants isolated for their nervous system phenotypes and studying their tracheal phenotypes. Results obtained so far show that many of these mutants have both axonal and tracheal phenotypes. Some of the genes identified so far and involved in both processes, will be discussed."

newsletter sent on 24/06/2009
CABD Seminar Cassandra Extavour, 12 June
SEMINARIOS DEL CABD

Friday, June 19th, @ 12

Dr. Bassem Hassan

VIB Department of Molecular and Developmental Genetics, Leuven, Belgium

Proneural genes as master switches in development and cancer

SUMMARY: The acquisition of terminal cell fate and onset of differentiation are instructed by cell type–specific master control genes. The Atonal group of bHLH transcription factors are master regulators of cell fate specification in the nervous systems and neuroendecrione lineages of all animals, presumably through regulating specific subsets of target genes. Despite enormous advances in our understanding of the genetics of cell fate specification, the molecular mechanisms of how these bHLH genes control cell fate acquisition and differentiation remain unknown. Interestingly, loss of differentiation is frequently observed during cancer progression, but the underlying causes and mechanisms remain poorly understood. We have undertaken an extensive analysis of the genetic interaction and gene regulatory networks that mediate the function of Drosophila Atonal. We find that Atonal principally regulates differential combinations of signal regulating molecules to specify diverse cell fates in the Drosophila PNS. Next, We tested the hypothesis that master regulators of differentiation may be key regulators of tumor formation. Using loss- and gain-of-function analyses in Drosophila, we describe a critical anti-oncogenic function for the atonal transcription factor in the fly retina. Next, we asked whether mouse Atoh1 and human ATOH1 also act as tumor suppressor genes in vivo. Genetic knockouts in mouse and molecular analyses in the mouse and in human cancer cell lines support a tumor suppressor function for ATOH1. The mechanisms by which Atonal suppresses tumor progression are highly conserved in fly, mouse and man.

 


newsletter sent on 16/06/2009
Extra CABD seminar Tomorrow 18 June

TOMOROW!!!!

Thursday, June 18th, @ 12
Dr. Diego Franco
DEPARTAMENTO DE BIOLOGÍA EXPERIMENTAL
, Universidad de Jaen

"Dissecting the role of Pitx2 mediating mRNA-microRNA  
signalling 
pathways during cardiac and skeletal myogenesis"

newsletter sent on 17/06/2009
CABD seminar Tomorrow 12 June
Friday 12th June



Epithelial morphogenesis: living on the edge.
Rui Gonçalo Martinho
Instituto Gulbenkian de Ciência, Oeiras
Portugal

Epithelial apicobasal (A/P) polarization is crucial for the correct formation and maintenance of adherens junctions (AJs). The establishment of A/P polarity relies on the mutual exclusion of the apical and basolateral components of the Par-aPKC (for ‘atypical protein kinase C’) system. The aPKC complex includes atypical protein kinase C (aPKC) and two PDZ-domain-containing proteins (Par3 and Par6). aPKC activity is crucial for A/P polarization and the correct formation and maintenance of AJs. We have isolated a temperature-sensitive allele of apkc (apkc-ts). Characterization of this allele during Drosophila development strongly suggests that epithelial tissues show distinct requirements for aPKC activity. Additionally, we also observed that at sub-optimal levels of aPKC activity, whereas some cells show loss of epithelial integrity, others within the same tissue and with the same genotype are apparently normal. We propose that different epithelial tissues will have distinct thresholds for aPKC activity depending on their “maturity”, proliferation and morphogenetic status. Additionally, we hypothesize that loss of epithelial integrity is usually “catastrophic” once the minimal aPKC activity requirements are not met.

Host: Acaimo González-Reyes
newsletter sent on 11/06/2009
CABD Seminar Dr. Vincent Mirouse Tomorrow@11

PLEASE NOTE TIME!
Tomorrow
Friday, May 22th, @ 11

Identification of a low energy epithelial polarity pathway
Dr. Vincent Mirouse
Clermont Université,
UFR Médecine, FRANCE


Tissue development requires control of cell morphogenesis, which includes, in many cases, acquisition of a cell polarity. Besides this morphogenesis, the size and the number of the cells must be also tightly regulated. Thus, development implies a coordination between cell morphogenesis and cell growth. Epithelium constitutes a good example to study this coordination because their architecture is relatively simple and well described. In this context, the ovarian follicular epithelium of Drosophila is an excellent model because this tissue has, on the one hand, an architecture representative of mammalian epithelia and, on the other hand,  a growth highly sensitive to external signals and notably controlled by food intakes. Thus, this model has allowed us to highlight the existence of a mechanism specifically required under conditions of nutrient deprivation, and especially energetic stress, for the establishment and maintenance of epithelial polarity. This mechanism involves several players of cell growth control, including the LKB1/AMPK pathway and the TOR kinase, which are necessary in these stress conditions to activate Myosin II, itself required for the establishment of epithelial polarity. Meanwhile, we showed that the transmembrane Dystrogylcan complex acts as a polarization cue in this mechanism, by controlling the localization of Myosin II in conditions of nutrient stress. Beyond the fundamental nature of this topic, it should be noted that over 80% of cancers are epithelial in origin and that they are associated, at least in their more aggressive phase, to a loss of cell polarity and of cell growth control. Moreover, all cancer cells change their way of producing ATP which leads to conditions of energetic stress ( "Warburg effect"). Our work, therefore, allows to combine these key features common to a vast majority of cancers, which are epithelial origin, energetic stress and a loss of cell polarity. In fact, many of the actors that we study are tumor suppressors or oncogenes in human and their involvement in the control of epithelial polarity under conditions of nutrient deprivation might explain, at least in part, their role in tumor development. and the remarkable ability to regenerate its germ line in vivo.

Host: Acaimo Gonzalez-Reyes
newsletter sent on 21/05/2009
CABD Seminar Cassandra Extavour, 8 May
Friday, May 8th, @ 12

Dr. Cassandra G. M. Extavour

Germline regeneration: theoretical predictions borne out by experimental observations
Department of Organismic and Evolutionary Biology, Harvard University, USA
Summary: Germ cells are often referred to as the “ultimate stem cell” as they produce daughter cells of all tissue types. Studies on laboratory genetic model systems suggest that germline differentiation is the result of one of two mechanisms, either (1) inheritance of cytoplasmic molecules necessary and sufficient for germ cell fate, or (2) signals from neighbouring cells conferring germ cell identity. These mechanisms are often viewed as being mutually exclusive, as no well-established genetic model organism employs both during wild type development. The phylogenetic distribution of these patterns across the Metazoa suggests that the signaling mode is ancestral, and that the inheritance mode must therefore have arisen independently in different lineages. We have developed a theoretical transitional model that unifies these observations. The model predicts that some developmental systems should exhibit both early
localisation of germ cell determinants, and the capacity to differentiate germ cells using inductive signals. Such animals could therefore be predicted to be able to regenerate lost germ cells. We show that careful examination of germ cell development in wild type and experimentally manipulated embryos of suitable model organisms can reveal the coexistence of both processes in the same animal, and the remarkable ability to regenerate its germ line in vivo.


newsletter sent on 06/05/2009
Plataforma Andaluza de Bioinformática - SCBI
SEMINARIOS DEL CABD

 NOTE: seminar will be held at the library/classroom

Friday, April 24th, @ 12

Dr. M. Gonzalo Claros Díaz

Universidad de Málaga.

    Presentación de la

Plataforma Andaluza de Bioinformática - SCBI




newsletter sent on 22/04/2009
CABD Seminar JM Mingot, 3rd April 2009


Friday, April 3rd, @ 12

Dr. J Manuel Mingot, Instituto de Neurociencias, CSIC-UMH, Alicante.

Summary: In eukaryotic cells two fundamental processes, transcription and translation take place in two different compartments, the nucleus and the cytoplasm, physically separated by a double membrane, the nuclear envelope. This separation makes absolutely necessary the existence of a nucleo-cytoplasmic transport (NCT). NCT processes take place through the nuclear pore complexes and are mainly mediated by nuclear transport receptors of the importin beta family. These proteins include importins, that mediate transport between the cytoplasm and the nucleus, exportins, that mediate the transport between the nucleus and the cytoplasm and Imp13, the only one so far described in higher eukaryotes that function both as an importin and as an exportin. NCT plays a fundamental role in the regulation of gene expression, as transcription factors among other proteins need to be translocated to the nucleus. Similarly, they need to be exported from the nucleus once they have fulfilled their role. In order to completely understand how transcription factors regulate gene expression, it is essential to know the mechanisms by which they are imported into or exported out of the nucleus as well as how these mechanisms are regulated. This knowledge is especially important in the case of transcription factor that, as the Snail proteins, play important roles during development or are involved in several pathologies during the adult live.

Host: A González-Reyes
newsletter sent on 01/04/2009
CABD seminar M Maroto

Please, note date!!!


Thursday, March 26th, @ 12

Dr. Miguel Maroto

Div. Cell & Developmental Biology

College of Life Sciences, University of Dundee

Scotland, U.K.

"New thoughts on the process of vertebrate segmentation"
 
Host: A González-Reyes
newsletter sent on 23/03/2009
CABD Seminar M Gotta, 25 March WED
PLEASE NOTE DAY!

Wednesday 25 of March

Cell polarity, cell fate and spindle positioning in C. elegans
Dr Monica Gotta,
Centre Médical Universitaire
GEDEV Department
Switzerland


Cell polarity, cell fate and spindle positioning in C. elegans

Asymmetric cell division is the process by which a cell divides to give origin to two cells that are different in fate. This is a fundamental process for the generation of cell diversity during development and for the self-renewal of stem cells. Asymmetric cell division relies first on the establishment of cell polarity and asymmetric localization of cell fate determinants. Subsequently, the mitotic spindle must be positioned properly, so that at division the cell fate determinants are unequally segregated to the two daughter cells. Using the C. elegans embryo as a model system, we have identified new factors required for polarity and spindle positioning using a combination of genetics, microscopy, biochemistry and functional genomics. I will present our work to understand how these factors contribute to regulation of cell polarity and spindle positioning in C. elegans.

Host: Peter Skjaer

newsletter sent on 12/03/2009
CABD Seminar, P Beldade Friday 13 March



Friday, March 13th, @ 12

Dr Patrícia Beldade.

The genetic and developmental basis of morphological diversification

Institute of Biology, University of Leiden, the Netherlands & Instituto Gulbenkian de Ciência, Portugal

Summary: Phenotypic variation is a universal characteristic of living organisms and understanding the genetic and developmental mechanisms underlying it is an important challenge in current biological research. Color patterns on butterfly wings present an ideal opportunity to study the reciprocal interactions between the developmental and evolutionary processes that shape morphological variation and account for the diversification of form. Two key features of morphological evolution, lineage-specific or novel traits (such as feathers in birds and carapaces in turtles) and serially repeated structures (such as body segments in insects and mammalian teeth), are beautifully represented in butterfly wings. Scale-based color patterns are novel traits in the Lepidoptera (butterflies and moths) and are made up of serially-repeated pattern elements, which have diversified across individual elements and across species. I will discuss experiments in a butterfly “lab rat” investigating the developmental mechanisms and specific genetic pathways that contribute to the formation, variation and diversification of those traits.

host F Casares
newsletter sent on 11/03/2009
CABD Seminar L Saude, 27 Feb



Feb 27: Dr. Leonor Saude, "Symmetry versus Asymmetry Decisions in the Vertebrate Embryo". IMM, Lisbon, Portugal.
newsletter sent on 06/02/2009
Extra CABD Seminar this wednesday

PLEASE NOTE DAY!!!!!

Wednesday, February 25th, @ 12


The little amphioxus: towards experimental Evo-Devo at the origin of chordates
Dr. Jordi Garcia-Fernandez
Dept Genetics, U. Barcelona

Summary: "Pallid anchovy fillet, friendly filtering, peacefully laying and little lancelet are some of the nicknames and adjectives the cephalochordate amphioxus has received throughout the last two centuries. Traditionally regarded as the living representative of the last ancestor of vertebrates, amphioxus has recently been promoted to the privileged position of being the most ancient chordate. The preliminary analysis of its prototypical genome and its hidden secrets towards the understanding of the primitive chordate and deuterostome genomes have just seen the light. I will sumarize here some of the characteristics of such genome; not only genome-wide conclusions, but also a detailed analysis of particular cases, like the Tyrosine Kinase superfamily or the neurogenic Iroquois cluster.

It seems that amphioxus embryonic development and body plan have remained in evolutionary stasis since the cephalochordate lineage split from the chordate ancestor about 500 Million years ago. But on the contrary, amphioxus research is far from being at a standstill; in Europe, thanks to the international cooperation and the Banyuls Oceanographic Station, amphioxus embryos are obtained on demand during the spawning season. I will summarise here our progress towards the dream of the experimental manipulation of the amphioxus embryo, to enter the era of Experimental Evo-Devo. Of course there is fear, expectations are high, the problems ahead multiple, but collaborators are top-class, and the excitement of helping discovering the hidden jewels of the genetic changes that generated, among other vertebrates, ourselves, compensate by far, the fear. For us, it is his moment, the momentum of the amphioxus.

host: JL G-Skarmeta
newsletter sent on 23/02/2009
CABD Seminar S Tiozzo 20 Feb

Feb 20: Dr. Stefano Tiozzo "Origin of regenerative plasticity and parasitic stem cells in basal chordates". Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, USA
newsletter sent on 06/02/2009
CABD Seminar, JM Frades Friday 13 Feb

Friday 13! Come at your own risk. Bad luck only spared to Spaniards.

Feb 13: Dr. Jose Maria Frades "Functional control of Notch during cell cycle in the vertebrate neuroepithelium: implications in neurogenesis" Instituto Cajal, CSIC, Madrid.
newsletter sent on 06/02/2009
Today's seminar (Now, Sorry)
Sorry for not announcing it earlier

Seminar is NOW (at 12:00)


Small-Open Readining Frame genes, Development and Evolution
Juan Pablo Couso,
Dept Biological Sciences,
Sussex University,
UK
newsletter sent on 30/01/2009
Tomorrow's CABD talk
Dr. José A. Horcajadas Almansa

“Functional Genomics of Human Endometrial Receptivity”

Functional Genomics of Human Endometrial Receptivity
Dr. José A. Horcajadas Almansa
Fundación IVI, Biomedical Future, UPO

Summary

Human embryo implantation requires a blastocyst stage embryo and a receptive endometrium. The endometrium is the inner surface of the uterus and is receptive only during a short time, around day 20 of the female cycle. This period of time is called the 'implantation window'. The accomplishment of this state is a complex molecular process which involves hundreds of genes. During the last years, Reproductive Medicine researchers have studied the endometrial gene expression profile in different receptivity stages (receptive, sub-receptive and non-receptive). Knowledge on these molecular factors involved in endometrial receptivity has great importance in order to understand implantation and to develop new contraceptive drugs and infertility treatments.


Host: M Muñoz
newsletter sent on 22/01/2009
First CABD Seminar 2009 TOMORROW
Feliz Año Nuevo/Happy New Year! and, please, note the seminar is TOMORROW!

CABD Seminars 2009

THURSDAY January 8th, @ 12

Claire Salzer

Retinal determination in Drosophila: within the developing eye and abroad.
Department of Biology
Indiana University, USA

Summary
Cell fate decisions are made throughout development to establish specialized organs and tissues and it is through the concerted action of multiple signaling pathways and specialized gene networks that body plans are set. Interestingly, many of the genes and signaling pathways that are responsible for the specification of one tissue are used repeatedly and throughout development to confer the fates of multiple tissues in organisms ranging from flies to mammals. Specification of the Drosophila eye is directed by a core group of ten Retinal Determination (RD) genes that make up a complex regulatory network. Through loss of function clonal analysis I have identified position dependent variations in the regulatory interactions occurring during retinal morphogenesis amongst several core members of the RD network. This implies that the network itself is not as fixed as previously believed, but regulatory interactions between genes are dynamically controlled both in time and space w
ithin the eye imaginal disc. One of the defining characteristics of an RD gene is that forced expression in non-retinal tissue can cause a change in tissue fate and consequently eyes develop in ectopic locations, such as the antenna, wings and legs. The ability to alter the fate of a tissue through expression of a single foreign gene suggests that the body plan, which we currently understand to be extremely rigid, may actually be quite flexible. I will present data suggesting that there is only a subset of cells in each developing appendage that retain developmental plasticity and are able to undergo this type of transformation.

Host: F Casares
----------------------------------------------
newsletter sent on 07/01/2009
CABD Christmas Special Seminar
PLEASE NOTE DATE! Wednesday, DECEMBER 17th, @ 12

Prof. Roger Patient
"On the origins and development of blood and cardiac adult stem cells"
Weatherall Institute of Molecular Medicine
University of Oxford; John Radcliffe Hospital
Headington, Oxford, UK

Summary

 Adult stem cells are developmentally interesting cells because they acquire the ability to resist differentiation, which is an essential and important part of their biology.  Using Xenopus and zebrafish as model organisms, we are studying the transcriptional programming of these cells with a view to understanding how this control is exerted.  In addition we are working out the signalling cascades that establish these programmes in the nucleus.  The archetypal stem cell is the blood stem cell and we have established a cellular hierarchy for this cell, assigned embryonic signals to progression through the hierarchy and are building transcriptional networks in the nucleus.  We have also begun to look at candidate cardiac stem cells and have uncovered an evolutionary angle on this problem, whereby a population of cells in the adult heart, which derives from the second heart field and exhibits multi-potentiality, may have evolved from a population of cells with blood and endothelial potential.  In this view the multi-potentiality may reflect in part an evolutionary memory of a more ancient programme.

We feel that a better understanding of the development of adult stem cells will facilitate their production and manipulation for regenerative therapies.
newsletter sent on 15/12/2008
Ectopic Seminar CABD (note time and date!)
PLEASE NOTE:
DAY TIME AND VENUE ARE NOT THE USUAL ONES

THURSDAY 21st November 2008
10:00h
CABD library

Post-translational modifications at the Synaptonemal Complex after DNA damage.
Dr. Tatiana Garcia-Muse (CABIMER)

We are using Caenorhabditis elegans as a model system to define the molecular events during meiosis progression in response to DNA damage. Meiosis is the specialized cell division by which diploid organisms generate haploid gametes key to sexual reproduction. Accurate segregation of chromosomes during meiosis is essential to re-establish a normal diploid genome at fertilization and in part depends on the correct assembly and disassembly of the protein scaffold known as the synaptonemal complex (SC).

We have observed phosphorylation events at the gonad in response to DNA damage during meiosis progression. In order to identify all potential phosphorylation sites in SC and meiotic proteins we have used the peptide array technique, which allows the study of molecular recognition events at the amino acid level.
(Host: Peter Askjaer)
newsletter sent on 18/11/2008
CABD Seminar, Gabriele Amore at 4PM
NOVEMBER 7, AT 4PM (PLEASE, NOTE THE h!)

Toward a more integrated view of regulation of gene expression

Dr. Gabriele Amore
Stazione Zoologica Napoli,
Italy.
host. F Casares

SUMMARY Control of gene expression is widely perceived as entirely controlled by the information encrypted in /cis/-regulatory regions.
However a long line of evidences, accumulating since the '70s, suggests that the compositional properties (GC level) of genomic DNA surrounding genes (genomic context) might affect the way genes work.
I will present some data showing how in sea urchin embryo, changing the compositional context of a GFP-reporter gene affect the way /cis/-regulatory information is utilized. I will also discuss some observations made on vertebrate genomes suggesting that what we found in the sea urchin embryo might be generally relevant to genome compositional evolution
newsletter sent on 03/11/2008
CABD Seminar, F.Martín-Belmonte, CBM-SO
Talk this Friday (24-10-2008) at 12
Salón de Actos CABD

Molecular characterization of epithelial morphogenesis using in vitro 3D models
Fernando Martín-Belmonte,
Centro de Biología Molecular Severo-Ochoa
C/ Nicolas Cabrera 1
Universidad Autónoma de Madrid
Madrid 28049


Host: James Castelli-Gair Hombría
newsletter sent on 20/10/2008
Tomorrow's CABD talk

newsletter sent on 11/09/2008
Patterning dynamic tissues in vertebrate embryos: A new role for extra-embryonic signals.
Dr. Scott Dougan, Department of Cellular Biology, University of Georgia, Athens, USA.
Host: JL Gomez-Skarmeta
newsletter sent on 30/06/2008
Next CABD seminar-note the time!
 Seminar will be at 10:30!!!
Benjamin Boettner,  
Van Aelst Lab, Cold Spring Harbor Laboratory, 1 Bungtown Road,
Cold Spring Harbor, NY 11724
The role of Rap1 signaling in adherens junction homeostasis and epithelial cell sorting processes
The morphogenesis of epithethelial tissues critically relies on the coherence of their constituent cells.  Intercellular coherence is brought about by adherens junctions (AJs) that have to be continuously maintained and during growth periods likely require extensive remodeling between sister cells in the late stages of cytokinesis.  In many expanding epithelia cohesion between sister cells emerging from cell division is fixed and perpetuated, which results in mitotic lineages that mostly display compact geometries within the tissue.  Deficiency of the small Rap1 GTPase encoding gene has been associated with a failure to properly remodel AJs in late cytokinesis.  In the model epithelium of the Drosophila wing imaginal disc Rap1 mutant cells loose cohesion and start to intermingle with and invade into non-mutant tissue.  Concomitantly, proper positional allocation and the compact appearance of mitotic lineages are significantly disrupted.  I will discuss effector functions of Rap1 in this process and will particularly focus on the multi-domain adaptor Canoe, a Drosophila homologue of the mammalian AF-6 and Afadin proteins, which have been involved in adherens junction biology and oncogenic processes.  Our analysis allows us to start explain the relationship of Rap1/Canoe signaling to other regulators of AJs, which I will discuss in the context of the ‘Differential Adhesion Hypothesis’.
newsletter sent on 09/09/2009
CABD Seminar Sep 25
 Friday 25-09-2009 at noon

Giorgio F. Gilestro Department of Psychiatry, 6001 Research Park Blvd, University of Wisconsin Madison, 53719, Madison WI, USA Synaptic Homeostasis and Sleep in Drosophila Sleep is a universally conserved behavior whose function still remains elusive. Our lab recently proposed a model for sleep function that links sleep need to the homeostatic regulation of synaptic strength, in a mutual bi-directional fashion. Using Drosophila as model system, we analyzed both directions of this connection. Using two different molecular markers of synapse number (the structural proteins BRP and DLG) and three markers of synaptic function (the components of vesicle secretion machinery: SYN, SYX, CSP) we investigated how sleep and wakefulness affect the dynamic regulation of bona fide synaptic strength in the Drosophila brain. We found that prolonged wakefulness induces a diffuse increase in synaptic number/volume, while restorative sleep has the opposite effect. Using two different paradigms of sleep deprivation we showed that the increase is specific to and correlate with the amount of time the flies spend being awake. Conversely, sleep-induced decrease in synaptic markers is proportional to the amount of time flies spend asleep and it is independent from circadian entrainment. Using confocal imaging, we showed that the increase in the expression of synaptic markers is widespread across the entire brain and that it correlated with a volumetric increase in specific area of the brain involved in learning. To manipulate synaptic function and strength, we ectopically expressed genes known to increase or decrease synaptic activity in vivo. We showed that a widespread increase in synaptic number in the Drosophila brain induces an increase in sleep drive and that, conversely, a decrease in synaptic number is followed by a decrease in sleep time. In particular, manipulation of synaptic activity (whether pan-neuronally or in specific area of the brain) affects length of sleep time, quality of sleep and recovery after sleep deprivation. In conclusion, our results suggest that, in flies, sleep regulates synaptic strength dynamics and synaptic strength regulates sleep need.

newsletter sent on 09/09/2009


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