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Ssu72 protein mediates both poly(A)-coupled and poly(A)-independent termination of RNA polymerase II transcription

Eric J Steinmetz1, David A Brow

  • 1Department of Biomolecular Chemistry, University of Wisconsin Medical School, 1300 University Avenue, Madison, WI 53706-1532, USA.

Molecular and Cellular Biology
|August 29, 2003
PubMed

Insights

Researchers identified a bipartite terminator in yeast small nuclear RNA genes. Mutations in the Ssu72 protein affect both Nrd1-dependent and poly(A)-dependent termination, suggesting a shared mechanism for RNA polymerase II termination.

Area of Science:

  • Molecular Biology
  • Eukaryotic Gene Expression
  • Transcription Termination

Background:

  • Termination of transcription by RNA polymerase II (Pol II) is crucial for gene expression but poorly understood.
  • Termination is linked to RNA signals that direct transcript cleavage and polyadenylation.
  • Nonpolyadenylated transcripts in yeast require specific RNA elements recognized by Nrd1.

Purpose of the Study:

  • To characterize the terminator of the SNR13 snoRNA gene.
  • To identify factors involved in the recognition of the SNR13 terminator.
  • To investigate the role of Ssu72 protein in transcription termination pathways.

Main Methods:

  • Genetic selection was used to analyze the SNR13 snoRNA gene terminator.
  • Genome-wide selection identified mutations affecting terminator recognition.
  • Analysis of mutations in the Ssu72 gene and their impact on termination.

Main Results:

  • The SNR13 terminator has a bipartite structure with Nrd1-binding and cleavage/polyadenylation-like elements.
  • Mutations in the essential Pol II-binding protein Ssu72 were identified.
  • An ssu72 mutation impaired both Nrd1-dependent and poly(A)-dependent termination.

Conclusions:

  • The findings reveal a bipartite structure for the SNR13 terminator.
  • Ssu72 plays a role in both Nrd1-dependent and poly(A)-dependent termination pathways.
  • These pathways likely share a common mechanism for signaling Pol II termination.

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