Expression patterns of Wnt8b and Wnt7b in the chicken embryonic brain suggest a correlation with forebrain patterning centers and morphogenesis

The expression patterns of the genes Wnt7b and Wnt8b were analyzed in the brain of chick embryos, having special emphasis in the forebrain. Our results indicated that, at early developmental stages, cWnt8b is expressed in the isthmic organizer and in other areas postulated as forebrain patterning centers, such as the avian cortical hem and the zona limitans intrathalamica (zli). Later in development, cWnt7b becomes expressed in regions neighboring and sometimes overlapping the cWnt8b domains, such as the thalamus on both sides of the zli, or the medial pallium adjacent to the cortical hem. This sequential expression of cWnt8b and cWnt7b is consistent with a role in the patterning and morphogenesis of these forebrain regions. (C) 2002 IBRO. Published by Elsevier Science Ltd. All rights reserved.