QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 16, Issue 3, 1152-1164, March 2005

This Article Full Text Full Text (PDF) All Versions of this Article: E04-07-0585v1 16/3/1152    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Martínez, S. E. Articles by Hake, L. E. Search for Related Content PubMed PubMed Citation Articles by Martínez, S. E. Articles by Hake, L. E.

XGef Mediates Early CPEB Phosphorylation during Xenopus Oocyte Meiotic Maturation

Susana E. Martínez ^*, Lei Yuan ^*, Charlemagne Lacza ^*, Heather Ransom ^*, Gwendolyn M. Mahon , Ian P. Whitehead , and Laura E. Hake ^*

^* Department of Biology, Boston College, Chestnut Hill, MA 02467; Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ 07103-2714

Submitted July 13, 2004; Revised November 24, 2004; Accepted December 22, 2004
Monitoring Editor: Joseph Gall

Polyadenylation-induced translation is an important regulatory mechanism during metazoan development. During Xenopus oocyte meiotic progression, polyadenylation-induced translation is regulated by CPEB, which is activated by phosphorylation. XGef, a guanine exchange factor, is a CPEB-interacting protein involved in the early steps of progesterone-stimulated oocyte maturation. We find that XGef influences early oocyte maturation by directly influencing CPEB function. XGef and CPEB interact during oogenesis and oocyte maturation and are present in a c-mos messenger ribonucleoprotein (mRNP). Both proteins also interact directly in vitro. XGef overexpression increases the level of CPEB phosphorylated early during oocyte maturation, and this directly correlates with increased Mos protein accumulation and acceleration of meiotic resumption. To exert this effect, XGef must retain guanine exchange activity and the interaction with CPEB. Overexpression of a guanine exchange deficient version of XGef, which interacts with CPEB, does not enhance early CPEB phosphorylation. Overexpression of a version of XGef that has significantly reduced interaction with CPEB, but retains guanine exchange activity, decreases early CPEB phosphorylation and delays oocyte maturation. Injection of XGef antibodies into oocytes blocks progesterone-induced oocyte maturation and early CPEB phosphorylation. These findings indicate that XGef is involved in early CPEB activation and implicate GTPase signaling in this process.

Address correspondence to: Laura E. Hake (hakel{at}bc.edu).

This article has been cited by other articles:

				L. Sun, R. Hodeify, S. Haun, A. Charlesworth, A. M. MacNicol, S. Ponnappan, U. Ponnappan, C. Prigent, and K. Machaca Ca2+ Homeostasis Regulates Xenopus Oocyte Maturation Biol Reprod, April 1, 2008; 78(4): 726 - 735. [Abstract] [Full Text] [PDF]

				B. T. Keady, P. Kuo, S. E. Martinez, L. Yuan, and L. E. Hake MAPK interacts with XGef and is required for CPEB activation during meiosis in Xenopus oocytes J. Cell Sci., March 15, 2007; 120(6): 1093 - 1103. [Abstract] [Full Text] [PDF]

				M. Rasar, D. B. DeFranco, and S. R. Hammes Paxillin Regulates Steroid-triggered Meiotic Resumption in Oocytes by Enhancing an All-or-None Positive Feedback Kinase Loop J. Biol. Chem., December 22, 2006; 281(51): 39455 - 39464. [Abstract] [Full Text] [PDF]