Coenzyme Q, given its relevant role as electron carrier in mitochondria, has not been studied in relation with other functions non related to the respiration but crucial to understanding processes such as the defense against stress and cellular ageing. Saccharomyces cerevisiae is a powerful eukaryotic model to unravel in detail these processes as it provides a huge number of technical and methodological advantages.

The aim of our research is double. We are analyzing expression of genes involved in the coenzyme Q biosynthesis pathway. At a transcriptional level we are monitoring it expression by competitive RT-PCR in different growth and oxidative stress conditions. We plan cloning and analyzing the promoter region to search for consensus sequences related to stress response. At a translational level, the expression of COQ genes during growth and in response to oxidative stress conditions will be performed with antibodies that we are developing. That study, immunoprecipitation analysis and FRET will be performed to study the interaction between the products of COQ genes required for the assembly of the coenzyme Q biosynthetic complex.
A second aspect of our research is focused in the study and characterization of an orphan gene of Saccharomyces cerevisiae encoding for a cytochrome b5 reductase located at the plasma membrane. This enzyme catalyzes coenzyme Q reduction using electrons from NADH. This enzyme modifies substantially the ratio NAD+/NADH producing a significant increase of the lifespan in these yeasts. Recent studies have shown that the action of this protein increasing lifespan requires the presence of the protein Sir2p, a histone deacetylase NAD+-dependent that blocks ageing produced by the ERCs accumulation (extrachromosome DNAr circles). Our aim is to perform a biochemical characterization of this protein, demonstrate its involvement in the life-span extension during caloric restriction processes and oxidative stress conditions.