Splicing factor SF3a6Oisthemammalian homologue of PRP9ofS.cerevisiae: theconserved zincfinger-like motif isfunctionally exchangeable invivo

A cDNAencoding the60kDasubunit ofmammalian splicing factor SF3ahasbeenisolated. Thededuced protein sequence reveals a30%identity tothePRP9 splicing protein oftheyeast S.cerevlsiae. Thehighest homology ispresent inazincfinger-like region inthe C-terminal domainofbothproteins. ThePRP9zinc finger-like motif hasbeenreplaced bytheequivalent region ofmammalian SF3a6O. Thechimeric protein rescues thetemperature-sensitive phenotype ofthe prp9-1 mutant strain demonstrating thatnotonlythe structure butalso thefunction ofthis domain hasbeen conserved during evolution.