Mrd1p is required for processing of pre-rRNA and for maintenance of steady-state levels of 40 S ribosomal subunits in yeast

J Biol Chem. 2002 May 24;277(21):18431-9. doi: 10.1074/jbc.M112395200. Epub 2002 Mar 7.

Abstract

Ribosome biogenesis is a conserved process in eukaryotes that requires a large number of small nucleolar RNAs and trans-acting proteins. The Saccharomyces cerevisiae MRD1 (multiple RNA-binding domain) gene encodes a novel protein that contains five consensus RNA-binding domains. Mrd1p is essential for viability. Mrd1p partially co-localizes with the nucleolar protein Nop1p. Depletion of Mrd1p leads to a selective reduction of 18 S rRNA and 40 S ribosomal subunits. Mrd1p associates with the 35 S precursor rRNA (pre-rRNA) and U3 small nucleolar RNAs and is necessary for the initial processing at the A(0)-A(2) cleavage sites in pre-rRNA. The presence of five RNA-binding domains in Mrd1p suggests that Mrd1p may function to correctly fold pre-rRNA, a requisite for proper cleavage. Sequence comparisons suggest that Mrd1p homologues exist in all eukaryotes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • DNA, Fungal
  • Fungal Proteins / genetics
  • Fungal Proteins / physiology*
  • Microscopy, Immunoelectron
  • RNA Processing, Post-Transcriptional / physiology*
  • RNA, Fungal / metabolism*
  • RNA, Ribosomal, 18S / metabolism*
  • Ribosomes / metabolism*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae / ultrastructure

Substances

  • DNA, Fungal
  • Fungal Proteins
  • RNA, Fungal
  • RNA, Ribosomal, 18S