Polypyrimidine tract binding protein inhibits igm pre-mrna splicing by diverting U2 snrna base-pairing away from the branch point

Xuexiu Zheng, Sunghee Cho, Heegyum Moon, Tiing Jen Loh, Huyn Kyung Oh, Michael R. Green, Haihong Shen

Research output: Contribution to journalArticleResearchpeer-review

4 Citations (Scopus)


The mouse immunoglobulin (IgM) pre-mRNA contains a splicing inhibitor that bears multiple binding sites for the splicing repressor polypyrimidine tract binding protein (PTB). Here we show that the inhibitor directs assembly of an ATP-dependent complex that contains PTB and U1 and U2 small nuclear RNAs (snRNAs). Unexpectedly, although U2 snRNA is present in the inhibitor complex, it is not base-paired to the branch point. We present evidence that inhibitor-bound PTB contacts U2 snRNA to promote base-pairing to an adjacent branch point-like sequence within the inhibitor, thereby preventing the U2 snRNA- branch point interaction and resulting in splicing repression. Our studies reveal a novel mechanism by which PTB represses splicing.

Original languageEnglish
Pages (from-to)440-446
Number of pages7
Issue number4
Publication statusPublished - Apr 2014
Externally publishedYes


  • Branch point
  • Polypyrimidine tract binding protein
  • Pre-mRNA splicing
  • PTB
  • Splicing inhibitory complex
  • U2 snRNA

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