Transgenic increase of Wnt7b in neural progenitor cells decreases expression of T-domain transcription factors and impairs neuronal differentiation

• Increased Wnt7b levels in neuronal progenitor cells in vivo decreases the number of beta-tubulin-III positive cells.
• Transgenic mouse embryos show decreased proportion of Tbr1- and Tbr2-expressing cells in the developing forebrain.
• Transgenic expression of Wnt7b does not affect the proportion of pax6+ neural progenitor cells at mid-gestation.

Wnt/beta-catenin signaling plays an important role in neural development, instructing both progenitor cell division and differentiation. During early corticogenesis, Wnt7b is expressed in a restricted expression pattern in the ventricular zone progenitor cells. However, its influence on progenitor cell behavior has not been fully studied. We report that transgenic overexpression of Wnt7b in neural progenitor cells impairs neuronal differentiation and the development of forebrain structures at embryonic day 10.5 (E10.5). This was accompanied by a decreased expression of T-domain transcription factors Tbr1 and Tbr2, in both progenitor cells and post-mitotic neurons. However, proliferation, apoptosis and the overall proportion of pax6+ neural progenitor cells were similar to wild-type litter mates. These results suggest that Wnt signaling may affect early neural progenitor differentiation by regulating the expression of pro-neural transcription factors.