CHox E, a chicken homeogene of the H2.0 type exhibits dorso-ventral restriction in the proliferating region of the spinal cord.

CHox E is a novel chicken homeogene that belongs to the H2.0 family of homeodomains. Its homeobox sequence is interrupted by an intron between amino acids 44 and 45. Expression of CHox E during embryogenesis is localized to the central nervous system. The anterior boundary of CHox E expression can initially be localized to rhombomere number 1, later in development this boundary reaches up to the rhombencephalic isthmus. CHox E expression in the spinal cord localizes dorso-ventrally to the dorsal half of the basal plate. CHox E expression is always restricted to the proliferating region, the ventricular zone. As the ventricular zone becomes restricted laterally, so does the CHox E expressing region. Once this region of the ventricular zone ceases to exist, CHox E specific transcripts become undetectable. The site and time of CHox E expression suggest a very early function in the differentiation of the cells derived from that region of the ventricular zone.