Beverdam Annemiek, Merlo Giorgio R, Paleari Laura, Mantero Stefano, Genova Francesca, Barbieri Ottavia, Janvier Philippe, Levi Giovanni
Laboratory of Molecular Morphogenesis, National Institute for Cancer Research, Genova, Italy.
Genesis. 2002 Dec;34(4):221-7. doi: 10.1002/gene.10156.
In modern vertebrates upper and lower jaws are morphologically different. Both develop from the mandibular arch, which is colonized mostly by Hox-free neural crest cells. Here we show that simultaneous inactivation of the murine homeobox genes Dlx5 and Dlx6 results in the transformation of the lower jaw into an upper jaw and in symmetry of the snout. This is the first homeotic-like transformation found in this Hox-free region after gene inactivation. A suggestive parallel comes from the paleontological record, which shows that in primitive vertebrates both jaws are essentially mirror images of each other. Our finding supports the notion that Dlx genes are homeotic genes associated with morphological novelty in the vertebrate lineage.
在现代脊椎动物中，上颌和下颌在形态上有所不同。两者均由下颌弓发育而来，而下颌弓主要由不含Hox的神经嵴细胞定植。在此我们表明，小鼠同源框基因Dlx5和Dlx6的同时失活会导致下颌向上颌转变以及口鼻部对称。这是基因失活后在这个不含Hox的区域发现的首个类同源异型转化。一个引人联想的相似情况来自古生物学记录，其显示在原始脊椎动物中，上下颌本质上是彼此的镜像。我们的发现支持了这样一种观点，即Dlx基因是与脊椎动物谱系中形态新奇性相关的同源异型基因。
