Caudalizing protein which is required to pattern the anterior/posterior (A/P) axis during central nervous system (CNS) formation. Inhibits anterior neural expression and acts as a transcriptional activator to induce posterior neural gene expression. Maintains a proper A/P balance required for hindbrain formation by activating the FGF/MAPK pathway, which modulates the planar cell polarity (PCP) pathway. Interacts with retinoid signaling during hindbrain patterning. In early-mid neurula stages, expressed in a single stripe in the neural plate. By neurula/early-tailbud stages, expression is localized to rhombomeres r2, r3 and r4 and the anterior spinal cord. Some ventral expression was also detected in posterior rhombomeres. Not expressed in rhombomere r1. Initially expressed at gastrula stages. Expression peaks at neurula stage, and is maintained at stable levels through tailbud stages. Belongs to the TALE/MEIS homeobox family.