Investigating the emerging role of spliceosome mutations in craniofacial development disorders

Pre-messenger RNA splicing is a key process in gene expression; however, the exact mechanisms of splicing are not well understood. This is partly due to the dynamic nature of the splicing agent, the spliceosome. This large RNA-protein assembly catalyses removal of introns from mRNA precursors and comprises five small nuclear RNPs that interact dynamically forming numerous complexes with the pre-mRNA. A number of rare genetic disorders due to mutation in core proteins of the spliceosome result in craniofacial disorders. We have recently identified mutations in the gene encoding the U5 snRNP spliceosome protein, TXNL4A, in Burn-McKeown syndrome. Therefore, spliceosome function is essential for normal craniofacial development but the underlying molecular mechanisms are not known.
This project aims to 1) determine how the disease associated mutations in the spliceosome protein genes influence spliceosome function using both human patient cells and yeast model systems, 2) use RNA-seq to identify the genes mis-spliced following mutations in the spliceosome protein genes then 3) study mouse models for these craniofacial disorders to determine how disease mutations influence craniofacial development.
The spliceosome protein genes mutated in these craniofacial disorders are highly conserved between humans, mice and yeast, which allows each system to be utilized. The student will investigate in human and yeast cells how mutations influence spliceosome assembly and known protein-protein interactions of the disease associated spliceosome proteins. Preliminary data suggests that mutations in TXNL4A reduce the expression of these proteins resulting in a decrease in assembly of the tri-snRNP U4/U6.U5 particle required for assembly of the active spliceosome. A combination of molecular biology, biochemical and genetic techniques will be used to determine how the disease mutations influence spliceosome function.
The student will determine why mutations in core spliceosome proteins, that are required for the splicing of all genes, only influence the splicing of a subset of genes by RNA-seq in both human and yeast cells to determine the genes that are mis-spliced resulting from disease associated mutations.To investigate the influence of the disease mutations on craniofacial development, the student will study mouse models for different craniofacial disorders to analyse the expression of the disease-associated spliceosome proteins during development in the specifc tissues.