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Nuclear Pnn/DRS protein binds to spliced mRNPs and participates in mRNA processing and export via interaction with

Chin Li1, Ru-Inn Lin, Ming-Chih Lai

  • 1Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.

Molecular and Cellular Biology
|October 1, 2003
PubMed

Insights

The Pnn/DRS protein interacts with splicing factors and binds to spliced mRNAs near splice junctions. Pnn may play a role in nuclear mRNA processing, including splicing and export.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • RNA Metabolism

Background:

  • The Pnn/DRS protein is localized to nuclear speckles and associates with splicing factors.
  • Its potential interaction with RNPS1, a pre-mRNA splicing factor, suggests a role in mRNA processing.

Purpose of the Study:

  • To investigate the involvement of Pnn in nuclear mRNA processing.
  • To determine the specific role of Pnn in mRNA splicing and export.

Main Methods:

  • Immunoprecipitation assays to detect Pnn-mRNA interactions.
  • Oligonucleotide-directed RNase H digestion to map Pnn binding sites.
  • Heterokaryon assays to determine protein localization.
  • Reporter gene assays and gene silencing to assess functional impact.

Main Results:

  • Pnn preferentially associates with spliced mRNAs, binding upstream of splice junctions.
  • 5' splice site utilization influences Pnn localization in alternatively spliced mRNAs.
  • Overexpression of a Pnn fragment inhibits pre-mRNA splicing, while Pnn suppression causes nuclear poly(A)(+) RNA accumulation.

Conclusions:

  • Pnn interacts with RNPS1 and participates in nuclear mRNA metabolism.
  • Pnn is involved in mRNA splicing and potentially mRNA export.
  • Pnn's function is linked to its interaction with splicing machinery and mRNA binding.

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