Synthetic lethal interactions with conditional poly(A) polymerase alleles identify LCP5, a gene involved in 18S rRNA maturation.
To identify new genes involved in 3'-end formation of mRNAs in Saccharomyces cerevisiae, we carried out a screen for synthetic lethal mutants with the conditional poly(A) polymerase allele, pap1-7. Five independent temperature-sensitive mutations called Icp1 to Icp5 (for lethal with conditional pap1 allele) were isolated. Here, we describe the characterization of the essential gene LCP5 which codes for a protein with a calculated molecular mass of 40.8 kD. Unexpectedly, we found that mutations in LCP5 caused defects in pre-ribosomal RNA (pre-rRNA) processing, whereas mRNA 3'-end formation in vitro was comparable to wild-type. Early cleavage steps (denoted A0 to A2) that lead to the production of mature 18S rRNA were impaired. In vivo depletion of Lcp5p also inhibited pre-rRNA processing. As a consequence, mutant and depleted cells showed decreased levels of polysomes compared to wild-type cells. Indirect immunofluorescence indicated a predominant localization of Lcp5p in the nucleolus. In addition, antibodies directed against Lcp5p specifically immunoprecipitated the yeast U3 snoRNA snR17, suggesting that the protein is directly involved in pre-rRNA processing.
Wiederkehr
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Department of Cell Biology, Biozentrum, University of Basel, Switzerland.
Prétôt
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Minvielle-Sebastia
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D000483:Alleles; D000595:Amino Acid Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020043:Genes, Essential / Q000235:genetics; D005800:Genes, Fungal / Q000235:genetics*; D005804:Genes, Lethal / Q000235:genetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D000073718:Pancreatitis-Associated Proteins; D010641:Phenotype; D011062:Polynucleotide Adenylyltransferase / Q000235:genetics*; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000235:genetics* / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000378:metabolism; D016601:RNA-Binding Proteins; D012270:Ribosomes / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins
D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C109242:FAL1 protein, S cerevisiae; D005656:Fungal Proteins; C115602:Lcp5 protein, S cerevisiae; D009687:Nuclear Proteins; D000073718:Pancreatitis-Associated Proteins; C105096:Pap1 protein, S pombe; C000612141:REG3A protein, human; D012331:RNA, Fungal; D012337:RNA, Ribosomal, 18S; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D011062:Polynucleotide Adenylyltransferase