Stability of a PKCI-1-related mRNA is controlled by the splicing factor ASF/SF2: a novel function for SR proteins

  1. Raphael Lemaire1,
  2. Jayendra Prasad2,
  3. Tsuyoshi Kashima2,
  4. Jennifer Gustafson1,
  5. James L. Manley2, and
  6. Robert Lafyatis1,3
  1. 1Boston University School of Medicine, The Arthritis Center, Boston, Massachusetts 02118, USA; 2Columbia University, Department of Biological Sciences, New York, New York 10027, USA

Abstract

Pre-mRNA splicing is a widely used regulatory mechanism for controlling gene expression, and a family of conserved proteins, SR proteins, participate in both constitutive and alternative splicing. Here we describe a novel function for the SR protein ASF/SF2. We used an embryonic chicken cDNA library to screen for differential mRNA expression in the chicken B-cell line DT40-ASF, expressing or not expressing ASF/SF2. Remarkably, out of 3 × 106 clones screened, only one, isolated several times independently, showed ASF/SF2-related differential expression. The isolated cDNA, referred to here as PKCI-r (for PKCI-related), is closely related to the protein kinase C interacting protein (PKCI-1) gene. Transcript levels were increased ∼sixfold in ASF/SF2-depleted cells compared with cells expressing ASF/SF2, indicating a negative role for the SR protein. Strikingly, inhibition of ASF/SF2 expression had no significant effect on PKCI-r splicing, or transcription, but markedly increased the half-life of PKCI-r mRNA (6.6-fold). Similarly, increased mRNA stability was also observed upon expression of exogenous PKCI-r mRNA in cells depleted of ASF/SF2. ASF/SF2 bound to a discrete region containing a purine-rich sequence in the 3′ UTR of the PKCI-r transcript, and deletion of this region eliminated ASF/SF2-mediated regulation of transcript stability. Together these data indicate a novel, direct effect of ASF/SF2 onPKCI-r mRNA stability. Therefore, ASF/SF2, and perhaps other SR proteins, affects gene expression in vertebrate cells through regulation of mRNA stability as well as splicing.

Keywords

Footnotes

  • 3 Corresponding author.

  • E-MAIL rlafyatis{at}med-med1.bu.edu; FAX (617) 638-5226.

  • Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.939502.

    • Received August 22, 2001.
    • Accepted January 18, 2002.
| Table of Contents

Life Science Alliance