Homeobox containing genes are a family of genes which have been shown in Drosophila to control pattern formation during development. These genes encode proteins which bind to DNA in a sequence specific manner. They contain a 180 bp conserved DNA domain called a homeobox. We have isolated several homeobox containing genes which are activated during early Xenopus development. We have determined their temporal and spatial expression pattern using Northern blot analysis and in situ hybridization. At least some of these genes are expressed during gastrulation, a critical time period of development at which mesodermal and neural induction takes place. Sequence analysis of these genes revealed that some of them are homologous to previously described genes in other species such as mouse and Drosophila, others have not yet been described. One of the genes which is homologous to the Drosophila Distal-less gene is likely to be involved in limb formation and regeneration. In addition, we have identified a novel gene family which has a similar function as the homeobox genes. They contain a conserved DNA binding motive - the fork head box. Our experiences show that these genes are involved in the regionalization of neural plate as well as mesoderm. The ultimate goal of the project is to understand how the normal development pattern is established and which of the genes play a critical role in this process. Understanding of these processes in frog will give us a better understanding of developmental malformations in humans.
