Distal-less genes Dlx1/Dlx2 repress oligodendrocyte genesis through transcriptional inhibition of Olig2 expression in the developing vertebrate forebrain

Abstract

In this study, we demonstrate that mouse DLX2 binds to the Olig2 gene locus in mouse embryonic forebrain in vivo. We further confirm the specificity and the transcriptional repressive effect of the binding in vitro. Furthermore, loss of Dlx1/2 function leads to increased Olig2 expression in the ventral embryonic mouse forebrain in vivo. As well, we demonstrate that chicken DLX1 binds to one chicken Olig2 gene domain in vitro, and overexpression of Dlx1 is sufficient to repress Olig2 expression in the developing chicken forebrain in ovo. Chicken DLX1 with a mutation eliminating its DNA binding ability is unable to bind to the Olig2 probe in vitro, and abrogates its repressive function on Olig2 expression in ovo. Our results establish that Dlx1/2 is both necessary and sufficient to repress oligodendrocyte specification mediated via direct transcriptional inhibition of Olig2 expression in the developing vertebrate forebrain.