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Polypyrimidine track-binding protein binding downstream of caspase-2 alternative exon 9 represses its inclusion

J Côté1, S Dupuis, J Y Wu

  • 1Department of Pediatrics and Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.

The Journal of Biological Chemistry
|December 16, 2000
PubMed

Insights

Alternative splicing of caspase-2 pre-mRNA regulates programmed cell death. A novel regulatory element (In100) controls exon 9 inclusion via two distinct domains, influencing apoptosis.

Area of Science:

  • Molecular Biology
  • RNA Splicing
  • Apoptosis Regulation

Background:

  • Alternative splicing of caspase-2 pre-mRNA is crucial for programmed cell death.
  • Exon skipping leads to isoforms with opposing apoptotic activities.
  • A negative regulatory element (In100) downstream of exon 9 was previously identified.

Purpose of the Study:

  • To further characterize the In100 element's regulatory mechanism on caspase-2 alternative splicing.
  • To investigate the role of PTB binding sites within the In100 element.
  • To elucidate how distinct domains of In100 contribute to exon 9 splicing regulation.

Main Methods:

  • Analysis of pre-mRNA splicing patterns.
  • Identification and characterization of regulatory elements and protein binding sites.
  • Functional assays to assess the impact of regulatory domains on alternative splicing.

Main Results:

  • The In100 element contains two functionally distinct domains that repress exon 9 inclusion.
  • A decoy 3' acceptor site in the upstream domain mediates nonproductive spliceosome interactions.
  • A downstream domain with PTB-binding sites also contributes to repression, with PTB binding modulating the decoy site's activity.

Conclusions:

  • Caspase-2 alternative splicing is regulated by a complex composite element (In100) with a novel mechanism.
  • Both domains of In100 independently repress exon 9 inclusion.
  • PTB binding influences the regulatory activity of the decoy splice site, highlighting intricate splicing control.

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