A functional dominant mutation in Schizosaccharomyces pombe RNase MRP RNA affects nuclear RNA processing and requires the mitochondrial-associated nuclear mutation ptp1-1 for viability.
The essential gene for RNase MRP RNA, mrp1, was identified previously in Schizosaccharomyces pombe by homology to mammalian RNase MRP RNAs. Here we describe distinct site-specific mutations in RNase MRP RNA that support a conserved role for this ribonucleoprotein in nucleolar 5.8S rRNA processing. One characterized mutation, mrp1-ND90, displays dominance and results in accumulation of unspliced precursor RNAs of dimeric tRNA(Ser)-tRNA(Met)i, suggesting a novel nuclear role for RNase MRP in tRNA processing. Cells carrying the mrp1-ND90 mutation, in the absence of a wild-type copy of mrp1, additionally require the mitochondrially associated nuclear mutation ptp1-1 for viability. Analysis of this mrp1 mutation reinforces previous biochemical evidence suggesting a role for RNase MRP in mitochondrial DNA replication. Several mutations in mrp1 result in unusual cellular morphology, including alterated nuclear organization, and are consistent with a broader nuclear role for RNase MRP in regulating a nuclear signal for septation; these results are a further indication of the multifunctional nature of this ribonucleoprotein.
Department of Developmental Biology, Stanford University School of Medicine, CA 94305-5427, USA.
J L
JL
Paluh
D A
DA
Clayton
D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D002872:Chromosome Deletion; D004722:Endoribonucleases / Q000235:genetics*; D005799:Genes, Dominant; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000235:genetics*; D012340:RNA, Ribosomal, 5.8S / Q000235:genetics; D012568:Schizosaccharomyces / Q000201:enzymology*
D012331:RNA, Fungal; D012340:RNA, Ribosomal, 5.8S; D004722:Endoribonucleases; C058330:mitochondrial RNA-processing endoribonuclease