The WNT Family of Cell Signalling Molecules in Postimplantation Development of the Mouse

Abstract

The mammalian Wnt gene family consists of at least ten members, allof which share a common structure. The N-terminus encodes a putative signalpeptide sequence, suggesting that Wnt proteins are secreted. A number of absolutelyconserved cysteine residues imply that inter- or intramolecular disulphide bondingis important to Wnt protein function. Wnt RNAs are localized to discrete regionsof the postimplantation embryo and fetus, particularly within the developing centralnervous system. Studies on Wnt gene expression strongly suggest that Wnt-mediatedsignalling is likely to be an important aspect of mouse development. One memberof the family, Wnt-1, has been studied in some detail. By generating mutant alleles,we have demonstrated that Wnt-1 regulates regional development of the centralnervous system at early somite stages. There is circumstantial evidence that someaspects of the pathway through which Wnt-1 action is mediated may beevolutionarily conserved. We propose that the Wnt family plays a major role incell–cell interactions in the mouse.

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