Messenger RNA production by RNA polymerase II (pol II) is central to the life of cells. The amount of messenger transcribed from each gene determines the amount of each corresponding protein that is made. For this reason, the process of mRNA synthesis, or transcription, is extremely carefully regulated by the cell. Corrupted regulation of mRNA synthesis is a major cause of cancer. Indeed, many of the oncogenes responsible for causing cancer, code for sequence specific transcription factors whose function is to control mRNA production. Our lab has found that certain transcription factors can stimulate the elongation of RNA transcripts by pol II. One aspect of our research is aimed at understanding the molecular basis for how elongation is controlled by transcription factors.
To make functional, a mRNA requires synthesis of a primary transcript and processing of the transcript into its mature form. The processing is carried out by a complex set of proteins which add a cap at the 5' end, splice out introns and add a polyA tail at the 3' end. Transcripts made by RNA polymerases other than pol II are not processed correctly into mature mRNA in vivo. A mechanism clearly exists to couple transcription by pol II with the specific RNA processing events responsible for maturation of mRNA and we are trying to work out its molecular details. Our lab uses genetic and biochemical approaches to ask how the transcriptional machinery interacts with the processing machinery to achieve coordinated synthesis and maturation of transcripts made by pol II. We have identified a protein domain at the C-terminus of the pol II large subunit called the CTD which is involved in targeting RNA processing factors to pol II transcripts. Our working hypothesis is that synthesis and processing of mRNA precursors is carried out in the nucleus by a 'mRNA factory' complex which comprises pol II and processing factors held together by contacts with the CTD.
- How does the pol II CTD influence elongation of transcripts in response to sequence specific activators and repressors?
- What genes are involved in control of transcriptional elongation by pol II in budding yeast?
- How does the cleavage/polyadenylation factor, CstF bind to the CTD and is this interaction necessary for mRNA 3’ processing in vivo?
- What is the role of the pol II CTD in processing of mRNAs in budding yeast?
- How does the CTD influence the RNA splicing reaction?
- Do sequence specific factors which regulate transcription also influence RNA processing?