RNA-binding protein conserved in both microtubule- and microfilament-based RNA localization

  1. Leora Havin1,3,
  2. Anna Git1,2,3,
  3. Zichrini Elisha1,
  4. Froma Oberman1,
  5. Karina Yaniv1,
  6. Sigal Pressman Schwartz1,
  7. Nancy Standart2, and
  8. Joel K. Yisraeli1,4
  1. 1Department of Anatomy and Cell Biology, Hebrew University Medical School, Jerusalem 91120, Israel; 2Department of Biochemistry, University of Cambridge, Old Addenbrookes Site, Cambridge CB2 1GA, UK

Abstract

Vg1 mRNA translocation to the vegetal cortex ofXenopus oocytes requires intact microtubules, and a 3′ UTRcis-acting element (termed VLE), which also mediates sequence-specific binding of several proteins. One protein, the 69-kD Vg1 RBP, associates Vg1 RNA to microtubules in vitro. Here we show that Vg1 RBP-binding sites correlate with vegetal localization. Purification and cloning of Vg1 RBP revealed five RNA-binding motifs: four KH and one RRM domains. Surprisingly, Vg1 RBP is highly homologous to the zipcode binding protein implicated in the microfilament-mediated localization of β actin mRNA in fibroblasts. These data support Vg1 RBP’s direct role in vegetal localization and suggest the existence of a general, evolutionarily conserved mechanism for mRNA targeting.

Keywords

Footnotes

  • 3 These authors contributed equally to this work.

  • 4 Corresponding author.

  • E-MAIL yisraeli{at}yam-suff.cc.huji.ac.il; FAX 972-2-675745.

    • Received January 21, 1998.
    • Accepted March 25, 1998.
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