Hoxa2 and Hoxb2 control dorsoventral patterns of neuronal development in the rostral hindbrain

Little is known about how the generation of specific neuronal types at ster eotypic positions within the hindbrain is linked to Hox gene-mediated patte rning. Here, we show that during neurogenesis, Hox paralog group 2 genes co ntrol both anteroposterior (A-P) and dorsoventral (D-V) patterning. Hoxa2 a nd Hoxb2 differentially regulate, in a rhombomere-specific manner, the expr ession of several genes in broad D-V-restricted domains or narrower longitu dinal columns of neuronal progenitors, immature neurons, and differentiatin g neuronal subtypes. Moreover, Hoxa2 and Hoxb2 can functionally synergize i n controlling the development of ventral neuronal subtypes in rhombomere 3 (r3). Thus, in addition to their roles in A-P patterning, Hoxa2 and Hoxb2 h ave distinct and restricted functions along the D-V axis during neurogenesi s, providing insights into how neuronal fates are assigned at stereotypic p ositions within the hindbrain.