Carapuço Marta, Nóvoa Ana, Bobola Nicoletta, Mallo Moisés
Instituto Gulbenkian de Ciencia, 2780-156 Oeiras, Portugal.
Genes Dev. 2005 Sep 15;19(18):2116-21. doi: 10.1101/gad.338705.
We show here that expression of Hoxa10 in the presomitic mesoderm is sufficient to confer a Hox group 10 patterning program to the somite, producing vertebrae without ribs, an effect not achieved when Hoxa10 is expressed in the somites. In addition, Hox group 11-dependent vertebral sacralization requires Hoxa11 expression in the presomitic mesoderm, while their caudal differentiation requires that Hoxa11 is expressed in the somites. Therefore, Hox gene patterning activity is different in the somites and presomitic mesoderm, the latter being very prominent for Hox gene-mediated patterning of the axial skeleton. This is further supported by our finding that inactivation of Gbx2, a homeobox-containing gene expressed in the presomitic mesoderm but not in the somites, produced Hox-like phenotypes in the axial skeleton without affecting Hox gene expression.
我们在此表明，在体节形成前的中胚层中Hoxa10的表达足以赋予体节一个Hox基因10模式程序，从而产生无肋骨的椎骨，而当Hoxa10在体节中表达时则无法实现这一效果。此外，Hox基因11依赖性的椎体骶化需要Hoxa11在体节形成前的中胚层中表达，而它们的尾部分化则要求Hoxa11在体节中表达。因此，Hox基因的模式形成活性在体节和体节形成前的中胚层中有所不同，后者在Hox基因介导的轴向骨骼模式形成中非常突出。我们发现，Gbx2（一个在体节形成前的中胚层而非体节中表达的含同源框基因）的失活在不影响Hox基因表达的情况下，在轴向骨骼中产生了类似Hox的表型，这进一步支持了上述观点。
