Structural basis of co-transcriptional pre-mRNA 3’-end processing

ended

RNAs transcribed by RNA polymerase II (Pol II) undergo numerous modifications before becoming export competent mature mRNA. One key step is the addition of the poly-adenine (poly-A) tail, which involves cleavage of the pre-mRNA from the growing RNA chain and the subsequent polyadenylation by poly-A polymerase. This cascade of events is known collectively as 3’-end processing and is one of the least understood steps of mRNA biogenesis. Pol II plays a vital role in recruiting and assembling the 3’-end processing machinery onto the nascent RNA, but the structural basis of transcription-coupled 3’-RNA processing is yet to be elucidated. This project aims to bring together the fields of transcription and 3’-end processing in order to understand how poly-A tails are added onto pre-mRNA in the context of actively transcribing Pol II. The most advanced methods of protein expression in recombinant systems as well as the extraction of complexes from native source will be coupled with state-of-the-art electron microscopy analysis to determine the structural basis of co-transcriptional 3’-end processing. Complementary biophysical methods will be used to map macromolecular interactions, and biochemical assays will be conducted to measure the impact of mutations introduced to characterize this fundamental biological process. The goal of this work is to provide the mechanistic basis for this essential step in mRNA biogenesis, and to understand human diseases that are resulted from aberrations in RNA production and processing.