Mutations affecting the tRNA-splicing endonuclease activity of Saccharomyces cerevisiae.
Two unlinked mutations that alter the enzyme activity of tRNA-splicing endonuclease have been identified in yeast. The sen1-1 mutation, which maps on chromosome 12, causes temperature-sensitive growth, reduced in vitro endonuclease activity, and in vivo accumulation of unspliced pre-tRNAs. The sen2-1 mutation does not confer a detectable growth defect, but causes a temperature-dependent reduction of in vitro endonuclease activity. Pre-tRNAs do not accumulate in sen2-1 strains. The in vitro enzyme activities of sen1-1 and sen2-1 complement in extracts from a heterozygous diploid, but fail to complement in mixed extracts from separate sen1-1 and sen2-1 haploid strains. These results suggest a direct role for SEN gene products in the enzymatic removal of introns from tRNA that is distinct from the role of other products known to affect tRNA splicing.
Winey
M
M
Laboratory of Genetics, University of Wisconsin, Madison 53706.
Culbertson
M R
MR
D004722:Endoribonucleases / Q000235:genetics*; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D007438:Introns; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*
D004722:Endoribonucleases; C051012:splicing endonuclease