Dr Sebastian Fica

Sebastian Fica

Our goal is to understand the molecular structure and dynamics of the spliceosome and thus to reveal the mechanisms that govern correct tissue-specific splicing and the coupling of splicing to transcription

Dr Sebastian Fica

Mechanisms and molecular structure of the spliceosome during pre-mRNA splicing

Mammalian genes are transcribed into precursor messenger RNAs (pre-mRNAs), from which non-coding introns are spliced out in the nucleus to produce mRNAs with continuous protein-coding information that can be exported to the cytoplasm and translated into protein. Through alternative splicing, introns expand proteomic diversity by allowing a single gene to encode multiple protein isoforms with distinct activities. Splicing is performed by the spliceosome - a dynamic assembly of RNA and proteins and splicing errors are implicated in at least 15% of human diseases.

Our goal is to understand the molecular mechanisms that govern correct tissue-specific splicing of different pre-mRNAs and the coupling of alternative splicing to transcription. Using electron cryo-microscopy, we have recently solved the first structures of catalytic intermediates of the yeast and human spliceosome. Human-specific proteins discovered in these structures can modulate spliceosome dynamics and regulate correct splice site use.

We aim to dissect in vitro the catalytic stage of human pre-mRNA splicing and combine biochemistry and electron cryo-microscopy to understand the molecular mechanisms that govern spliceosome dynamics, splice site selection, and proofreading during catalysis. We are excited to explore the possibility that alternative splicing, normally studied during initial spliceosome assembly, may also be regulated during catalysis by transcript-specific splicing factors. To extend our in vitro findings, we use crosslinking and sequencing approaches (e.g. CLIP, RNA-seq) to understand how these factors act genome-wide in vivo in cell culture. We hope to discover novel splicing factors and reveal fundamental insights into regulation of alternative splicing in specific tissues and developmental states.

To find out more visit our lab website; https://snrnpsplicingbiochemlab.web.ox.ac.uk