Prp45 Affects Prp22 Partition in Spliceosomal Complexes and Splicing Efficiency of Non-Consensus Substrates
Abstract
Prp45 is an yeast ortholog of Human transcription co-regulator SNW1/SKIP, which is implicated in the regulation of both transcription elongation and alternative splicing. We characterize a temperature sensitive allele of PRP45 using a synthetic lethality screen, TAP purification and primer extension splicing assay.
We found that prp45(1-169) genetically interacts spliceosomal components SYF1, CLF1/SYF3, NTC20, and CEF1, SLU7, PRP17, PRP18, and PRP22. Spliceosomal complexes purified from prp45(1-169) cells showed decreased stoichiometry of Prp22, suggesting its deranged interaction with the spliceosome.
Splicing of canonical intron was unimpeded, wheras mutants showed elevated levels of lariatexon intermediate. We suggest that Prp45 contributes to splicing efficiency of substrates non-conforming to the consensus.