SSB-1 of the yeast Saccharomyces cerevisiae is a nucleolar-specific, silver-binding protein that is associated with the snR10 and snR11 small nuclear RNAs

J Cell Biol. 1990 Nov;111(5 Pt 1):1741-51. doi: 10.1083/jcb.111.5.1741.

Abstract

SSB-1, the yeast single-strand RNA-binding protein, is demonstrated to be a yeast nucleolar-specific, silver-binding protein. In double-label immunofluorescence microscopy experiments antibodies to two other nucleolar proteins, RNA Pol I 190-kD and fibrillarin, were used to reveal the site of rRNA transcription; i.e., the fibrillar region of the nucleolus. SSB-1 colocalized with fibrillarin in a double-label immunofluorescence mapping experiment to the yeast nucleolus. SSB-1 is located, though, over a wider region of the nucleolus than the transcription site marker. Immunoprecipitations of yeast cell extracts with the SSB-1 antibody reveal that in 150 mM NaCl SSB-1 is bound to two small nuclear RNAs (snRNAs). These yeast snRNAs are snR10 and snR11, with snR10 being predominant. Since snR10 has been implicated in pre-rRNA processing, the association of SSB-1 and snR10 into a nucleolar snRNP particle indicates SSB-1 involvement in rRNA processing as well. Also, another yeast protein, SSB-36-kD, isolated by single-strand DNA chromatography, is shown to bind silver under the conditions used for nucleolar-specific staining. It is, most likely, another yeast nucleolar protein.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies
  • Autoantibodies
  • Autoantigens / analysis*
  • Carrier Proteins / analysis*
  • Chromosomal Proteins, Non-Histone / immunology
  • DNA-Binding Proteins / analysis
  • Fluorescent Antibody Technique
  • Fungal Proteins / analysis*
  • Humans
  • Microscopy, Fluorescence
  • Molecular Weight
  • Nucleolus Organizer Region / chemistry*
  • Precipitin Tests
  • RNA Processing, Post-Transcriptional
  • RNA, Fungal / metabolism*
  • RNA, Ribosomal / metabolism
  • RNA, Small Nuclear / metabolism*
  • RNA-Binding Proteins
  • Ribonucleoproteins*
  • Ribosomes / metabolism
  • SS-B Antigen
  • Saccharomyces cerevisiae / analysis*
  • Saccharomyces cerevisiae / genetics
  • Silver / metabolism
  • Sodium Chloride

Substances

  • Antibodies
  • Autoantibodies
  • Autoantigens
  • Carrier Proteins
  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • Fungal Proteins
  • RNA, Fungal
  • RNA, Ribosomal
  • RNA, Small Nuclear
  • RNA-Binding Proteins
  • Ribonucleoproteins
  • fibrillarin
  • Silver
  • Sodium Chloride