Homeobox genes as regulators of vertebrate development.

摘要: A review. The Hox genes are a family of genes isolated from vertebrate genomes based on a conserved sequence domain, the homeo box, originally found in Drosophila homeotic genes. Not only essential parts of the genes, but also the genomic organization in gene clusters, is conserved and duplicated during evolution. Higher vertebrates have 38 Hox genes organised in 4 Hox clusters on different chromosomes. Expression patterns have been determined for many of these genes. Overlapping but identical expression domains indicate a relation to the axial level rather than to a specific tissue. Regulatory elements involved in establishing these unusual patterns of expression have been identified in transgenic mice expressing the bacterial lacZ gene under the control of Hox DNA fragments. Distinct combinations of expressed Hox genes, the Hox codes, are characteristic of distinct segments of the vertebrate …