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Dynamic expression of Lef/Tcf family members and β‐catenin during chick gastrulation, neurulation, and early limb development

Members of the Lef/Tcf family of HMG‐box transcription factors mediate the response to Wnt as part of the canonical Wnt signaling cascade. Positive and negative cofactors, including β‐catenin, CtBP, and Smad3, regulate the activity of Lef/Tcf transcription complexes. Interaction of Lef/Tcfs with β‐catenin results in target gene activation or repression, depending on the context. Here, we report the cloning of a novel chick Tcf‐1 splice variant and of a partial cDNA for chick Tcf‐3. We describe their expression patterns during early development and have compared them with the expression profiles of Lef‐1 and β‐catenin. We found restricted patterns during gastrulation, neurulation, somitogenesis, and early limb development. β‐catenin and Lef/Tcf expression did not always coincide, indicating developmental contexts in which Lef/Tcf proteins may interact with other cofactors and conversely, the areas in which β‐catenin may interact with other coregulators, or be involved in regulating adhesive properties of cells. Developmental Dynamics 229:703–707, 2004. © 2004 Wiley‐Liss, Inc.