The splicing factor Prp43p, a DEAH box ATPase, functions in ribosome biogenesis

Mol Cell Biol. 2006 Jan;26(2):513-22. doi: 10.1128/MCB.26.2.513-522.2006.

Abstract

Biogenesis of the small and large ribosomal subunits requires modification, processing, and folding of pre-rRNA to yield mature rRNA. Here, we report that efficient biogenesis of both small- and large-subunit rRNAs requires the DEAH box ATPase Prp43p, a pre-mRNA splicing factor. By steady-state analysis, a cold-sensitive prp43 mutant accumulates 35S pre-rRNA and depletes 20S, 27S, and 7S pre-rRNAs, precursors to the small- and large-subunit rRNAs. By pulse-chase analysis, the prp43 mutant is defective in the formation of 20S and 27S pre-rRNAs and in the accumulation of 18S and 25S mature rRNAs. Wild-type Prp43p immunoprecipitates pre-rRNAs and mature rRNAs, indicating a direct role in ribosome biogenesis. The Prp43p-Q423N mutant immunoprecipitates 27SA2 pre-rRNA threefold more efficiently than the wild type, suggesting a critical role for Prp43p at the earliest stages of large-subunit biogenesis. Consistent with an early role for Prp43p in ribosome biogenesis, Prp43p immunoprecipitates the majority of snoRNAs; further, compared to the wild type, the prp43 mutant generally immunoprecipitates the snoRNAs more efficiently. In the prp43 mutant, the snoRNA snR64 fails to methylate residue C2337 in 27S pre-rRNA, suggesting a role in snoRNA function. We propose that Prp43p promotes recycling of snoRNAs and biogenesis factors during pre-rRNA processing, similar to its recycling role in pre-mRNA splicing. The dual function for Prp43p in the cell raises the possibility that ribosome biogenesis and pre-mRNA splicing may be coordinately regulated.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / physiology*
  • DEAD-box RNA Helicases
  • Mutation
  • RNA Helicases / genetics
  • RNA Helicases / physiology*
  • RNA Precursors / genetics*
  • RNA Precursors / physiology
  • RNA Splicing / genetics*
  • RNA Splicing / physiology
  • RNA, Small Nuclear / genetics
  • RNA, Small Nuclear / physiology
  • RNA, Small Nucleolar / metabolism
  • Ribosomes / genetics*
  • Ribosomes / physiology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / physiology
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / physiology*

Substances

  • RNA Precursors
  • RNA, Small Nuclear
  • RNA, Small Nucleolar
  • Saccharomyces cerevisiae Proteins
  • Adenosine Triphosphatases
  • PRP43 protein, S cerevisiae
  • DEAD-box RNA Helicases
  • RNA Helicases