The production of messenger RNA in eukaryotic cells involves precursor mRNA (pre-mRNA) synthesis and processing. During splicing, the spliceosome removes noncoding introns from pre-mRNA in a co-transcriptional manner on the surface of RNA polymerase II (Pol II). Co-transcriptional splicing enhances the efficiency and accuracy of pre-mRNA processing and explains why splicing is at least 10 times faster in vivo than in vitro. In particular, co-transcriptional splicing has been suggested to be essential in metazoan cells where introns are often several thousand nucleotides long, raising the intriguing question of how these distant intron ends are functionally paired for splicing.
Our lab’s research focuses on how the transcription and splicing machineries crosstalk to regulate splicing and alternative splicing in human. Alternative splicing is critical for generating proteomic diversity and plays a pivotal role in cell growth, differentiation and death. Regulation of splicing and alternative splicing is intricately coupled with transcription, defining a complex regulatory mechanism for gene expression, yet the underlying mechanisms remain unclear. We previously determined the cryo-EM structure of a transcribing Pol II-U1 snRNP complex, where U1 snRNP is the first spliceosomal building block to engage the pre-mRNA. The structure revealed a direct physical interaction between Pol II and U1 snRNP, positioning the 5’ splice site at the RNA exit site of Pol II, and providing mechanistic insights into the first step of co-transcriptional splicing.
This PhD project aims to understand the molecular interactions between the transcription and splicing machineries and how these interactions facilitate efficient and accurate splicing and affect the outcome of alternative splicing. Successful candidate will gain experiences and knowledge in in vitro reconstitution of large protein-nucleic acid complexes, biochemical assays and the cutting-edge structural biology with a focus on cryo-electron microscopy. Please feel free to contact me for more detailed discussion of the project.
References
Primary literature:
Zhang S, Aibara S, Vos SM, Agafonov DE, Lührmann R, Cramer P. (2021)Structure of a transcribing RNA polymerase II-U1 snRNP complex. Science 371(6526):305-309. doi: 10.1126/science.abf1870.
Nojima T, Rebelo K, Gomes T, Grosso AR, Proudfoot NJ, Carmo-Fonseca M. (2018) RNA Polymerase II Phosphorylated on CTD Serine 5 Interacts with the Spliceosome during Co-transcriptional Splicing. Mol Cell.18;72(2):369-379.e4. doi: 10.1016/j.molcel.2018.09.004.
Reviews:
Giono LE, Kornblihtt AR. (2020) Linking transcription, RNA polymerase II elongation and alternative splicing. Biochem J. 477(16):3091-3104. doi: 10.1042/BCJ20200475.
Tellier M, Maudlin I, Murphy S. (2020) Transcription and splicing: A two-way street. Wiley Interdiscip Rev RNA. 11(5):e1593. doi: 10.1002/wrna.1593.