Hoxb-1 maintains this function by acting very early during hindbrain neurogenesis to specify effectors of the sonic hedgehog and Mash1 signaling pathways. Hoxb2 is a homeodomain protein important in neural development that is also expressed during erythropoiesis, hindbrain development and normal human adult lung development. Hoxb2 may modulate the amount of gamma-globin mRNA expressed during development and differentiation. In addition, Hoxb2 plays an important role in the patterning of hindbrain and pharyngeal arches in the zebrafish.