Synthetic lethal interactions with conditional poly(A) polymerase alleles identify LCP5, a gene involved in 18S rRNA maturation

RNA. 1998 Nov;4(11):1357-72. doi: 10.1017/s1355838298980955.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles*
  • Amino Acid Sequence
  • Basic-Leucine Zipper Transcription Factors
  • DNA-Binding Proteins / genetics
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Genes, Essential / genetics
  • Genes, Fungal / genetics*
  • Genes, Lethal / genetics
  • Molecular Sequence Data
  • Mutagenesis
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Pancreatitis-Associated Proteins
  • Phenotype
  • Polynucleotide Adenylyltransferase / genetics*
  • Polyribosomes / metabolism
  • Protein Biosynthesis / genetics
  • RNA Processing, Post-Transcriptional*
  • RNA, Fungal / genetics
  • RNA, Fungal / metabolism
  • RNA, Ribosomal, 18S / genetics*
  • RNA, Ribosomal, 18S / metabolism
  • RNA, Small Nuclear / metabolism
  • RNA-Binding Proteins*
  • Ribosomes / metabolism
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins*
  • Schizosaccharomyces pombe Proteins

Substances

  • Basic-Leucine Zipper Transcription Factors
  • DNA-Binding Proteins
  • FAL1 protein, S cerevisiae
  • Fungal Proteins
  • Lcp5 protein, S cerevisiae
  • Nuclear Proteins
  • Pancreatitis-Associated Proteins
  • Pap1 protein, S pombe
  • REG3A protein, human
  • RNA, Fungal
  • RNA, Ribosomal, 18S
  • RNA, Small Nuclear
  • RNA-Binding Proteins
  • Saccharomyces cerevisiae Proteins
  • Schizosaccharomyces pombe Proteins
  • Polynucleotide Adenylyltransferase