Int. J. Dev. Biol. 46: 731 - 739 (2002)
© UPV/EHU Press

Differential post-transcriptional regulations of wnt mRNAs upon axolotl meiotic maturation.

Sabine Vaur, Nicole Montreau, François Dautry and Yannick Andéol

Laboratoire des régulationspost-transcriptionnelles, Institut André Lwoff, CNRS, UPR 1983, Villejuif, France.

ABSTRACT The products of the Wntgene family play an essential role in several aspects of embryo patterning. We have investigated the post-transcriptional regulation of three of these genes: Awnt-1, Awnt-5A and Awnt-5B during axolotl (Ambystoma mexicanum) oogenesis, oocyte maturation and early development. We show that Awnt-1, Awnt-5A and Awnt-5B mRNAs are maternally expressed. The three transcripts are tightly regulated at specific times and display differential mRNA stability, poly(A) tail length and localization. In contrastto Awnt-5Bwhich is restricted to the animal hemisphere, Awnt-1 and Awnt-5A have no particular localization in stage VI oocytes. Interestingly, these two mRNAs exhibit a polyadenylation gradient along the animal-vegetal axis. Moreover, after meiotic maturation, Awnt-1 and 5A mRNAs become exclusively localized to the animal pole. This isthe first evidence of a complete mRNA re-localization to the animal hemisphere during oocyte maturation.