A polypyrimidine tract-binding protein-dependent pathway of mRNA stability initiates with CpG activation of primary B cells

Joseph F. Porter, Stefano Vavassori, Lori R. Covey

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

The mRNA encoding CD154, a critical protein involved in both humoral and cell-mediated immune responses, is regulated at the posttranscriptional level by the binding of complex I, a polypyrimidine tract-binding (PTB) protein-containing complex, which acts to increase message stability at late times of activation. Our current work focuses on analyzing a similar complex in B cells, designated B-cpx I, which is increased in B cells activated by CpG engagement of the TLR9 receptor but not by activation through CD40. Expression profiling of transcripts from primary B cells identified 31 mRNA transcripts with elevated PTB binding upon activation. Two of these transcripts, Rab8A and cyclin D2, contained binding sites for B-cpx I in their 3′ untranslated regions (UTRs). Analysis of turnover of endogenous Rab8A transcript in B cells revealed that like CD154, the mRNA half-life increased following activation and insertion of the Rab8A B-cpx I binding site into a heterologous transcript led to a 3-fold increase in stability. Also, short hairpin RNA down-regulation of PTB resulted in a corresponding decrease in Rab8A mRNA half-life. Overall these data strongly support a novel pathway of mRNA turnover that is expressed both in T cells and B cells and depends on the formation of a PTB-containing stability complex in response to cellular activation.

Original languageEnglish (US)
Pages (from-to)3336-3345
Number of pages10
JournalJournal of Immunology
Volume181
Issue number5
DOIs
StatePublished - Sep 1 2008

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology

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