A putative ATP binding protein influences the fidelity of branchpoint recognition in yeast splicing.
We previously described a dominant suppressor of the splicing defect conferred by an A----C intron branchpoint mutation in S. cerevisiae. Suppression occurs by increasing the frequency with which the mutant branchpoint is utilized. We have now cloned the genomic region encoding the prp16-1 suppressor function and have demonstrated that PRP16 is essential for viability. A 1071 amino acid open reading frame contains sequence motifs characteristic of an NTP binding fold and further similarities to a superfamily of proteins that includes members with demonstrated RNA-dependent ATPase activity. A single nucleotide change necessary to confer the prp16-1 suppressor phenotype results in a Tyr----Asp substitution near the "A site" consensus for NTP binding proteins. We propose that PRP16 is an excellent candidate for mediating one of the many ATP-requiring steps of spliceosome assembly and that accuracy of branchpoint recognition may be coupled to ATP binding and/or hydrolysis.
Burgess
S
S
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Couto
J R
JR
Guthrie
C
C
D000251:Adenosine Triphosphatases / Q000235:genetics*; D000595:Amino Acid Sequence; D001224:Aspartic Acid; D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D015723:Gene Library; D005799:Genes, Dominant; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D012326:RNA Splicing; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013489:Suppression, Genetic; D014443:Tyrosine
D001224:Aspartic Acid; D014443:Tyrosine; D000251:Adenosine Triphosphatases; C027900:RNA-dependent ATPase