Grant: Project Grant

For a gene to "express" itself and contribute to the function of the cell that hosts it, it first needs to be transcribed. Gene transcription consists of making a copy of the gene as an RNA molecule. This RNA molecule is then translated into a protein. The enzyme that generates RNAs from genes coding for proteins is called RNA polymerase II (RNAPII). This enzyme contains a peculiar domain called CTD, made of several repetitions of a small amino acid chain. The CTD is essential for cell viability and is evolutionarily conserved. Two decades of research taught us that the CTD serves as a docking platform for several proteins to join RNAPII during the transcription of genes, a process notably important for the transcribed RNA to become competent to be translated. More recently, several research groups have proposed different roles for the CTD. According to these studies, the CTD, rather than docking proteins, would rather make "hit and run" interactions with other CTD molecules and other proteins, creating zones in the cell nucleus where RNAPII is found in high concentrations, which would then favor more efficient transcription of the neighboring genes. These more recent models are radically different from the traditional view of CTD function. Our preliminary results investigating this dichotomy prompt us to propose that both models are co-existing. We propose that this is made possible by the repetitive nature of the CTD and that different segments of the CTD are dedicated to different aspects of its function.