GSBS Student Publications

Title

Translational unmasking of Emi2 directs cytostatic factor arrest in meiosis II

UMMS Affiliation

Graduate School of Biomedical Sciences; Genentech; Program in Molecular Medicine

Date

3-16-2007

Document Type

Article

Medical Subject Headings

Animals; F-Box Proteins; Female; Meiosis; Oocytes; Protein Biosynthesis; Proto-Oncogene Proteins c-mos; Rabbits; Xenopus; Xenopus Proteins

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Cytostatic factor (CSF) arrests unfertilized vertebrate eggs in metaphase of meiosis II by inhibiting the anaphase-promoting complex/cyclosome (APC/C) from mediating cyclin destruction. The APC/C inhibitor Emi2/XErp1 satisfies a number of historical criteria for the molecular identification of CSF, but the mechanism by which CSF is activated selectively in meiosis II is the remaining unexplained criterion. Here we provide an explanation by showing that Emi2 is expressed specifically in meiosis II through translational de-repression or "unmasking" of its mRNA. We find that Emi2 protein is undetectable in immature, G2/prophase-arrested Xenopus oocytes and accumulates approximately 90 minutes after germinal vesicle breakdown. The 3' untranslated region of Emi2 mRNA contains cytoplasmic polyadenylation elements that directly bind the CPEB protein and confer temporal regulation of Emi2 polyadenylation and translation. Our results demonstrate that cytoplasmic polyadenylation and translational unmasking of Emi2 directs meiosis II-specific CSF arrest.

Rights and Permissions

Citation: Cell Cycle. 2007 Mar 15;6(6):725-31. Epub 2007 Mar 1.

Related Resources

Link to Article in PubMed

Journal Title

Cell cycle (Georgetown, Tex.)

PubMed ID

17361107