Genome-wide distribution of Pbx1/2/3 in mouse cortex at embryonic day 15.5 [ChIP-seq]

We demonstrate using conditional mutagenesis that Pbx1, with and without Pbx2+/ sensitization, regulates regional identity and laminar patterning of the developing mouse neocortex in cortical progenitors (Emx1-Cre) and in newly generated neurons (Nex1-Cre). Pbx1/2 mutants have three salient molecular phenotypes of cortical regional and laminar organization: hypoplasia of the frontal cortex, ventral expansion of the dorsomedial cortex, and ventral expansion of Reelin expression in the cortical plate of the frontal cortex, concomitant with an inversion of cortical layering in the rostral cortex. Molecular analyses, including PBX ChIP-seq, provide evidence that PBX promotes frontal cortex identity by repressing genes that promote dorsocaudal fate. Chromatin immunoprecipitation was performed using antibody against Pbx1/2/3 (sc-888, Santa Cruz). Wild type E15.5 mouse whole cortex was used for the analysis.