| This proposal is concerned with elucidating gene cascades which pattern the main body axis in the vertebrate embryo. It has now become clear that the maternal/gap/segmentation/hox gene hierarchy which establishes anteroposterior pattern and regulates early Hox gene expression in Drosophila, is not highly conserved in vertebrates. Some relevant Drosophila genes, like the maternal effect gene bicoid have no known vertebrate orthologues. Others, like the pair rule gene even skipped and the gap gene tailless, have orthologues, but not conserved functions. Hox genes are conserved, but their upstream regulation is not. Most strikingly, with one notable exception (below), there are no recognised vertebrate equivalents of gap genes. The intention for this project is investigate the concept that a mechanism functionally homologous to the Drosophila gap gene network maps out the main zones of the vertebrate anteroposterior axis. We are specifically concerned with the cascades mediating establishment and patterning of a mid-axial zone during gastrulation. |
