Mathers P H, Grinberg A, Mahon K A, Jamrich M
Laboratory of Developmental Biology, Food and Drug Administration, Rockville, Maryland 20852, USA.
Nature. 1997 Jun 5;387(6633):603-7. doi: 10.1038/42475.
Development of the vertebrate eye requires a series of steps including specification of the anterior neural plate, evagination of the optic vesicles from the ventral forebrain, and the cellular differentiation of the lens and retina. Homeobox-containing genes, especially the transcription regulator Pax6, play a critical role in vertebrate and invertebrate eye formation. Mutations in Pax6 function result in eye malformations known as Aniridia in humans and Small eye syndrome in mice. The Drosophila homologue of Pax6, eyeless, is also necessary for correct invertebrate eye development, and its misexpression leads to formation of ectopic eyes in Drosophila. Here we show that a conserved vertebrate homeobox gene, Rx, is essential for normal eye development, and that its misexpression has profound effects on eye morphology. Xenopus embryos injected with synthetic Rx RNA develop ectopic retinal tissue and display hyperproliferation in the neuroretina. Mouse embryos carrying a null allele of this gene do not form optic cups and so do not develop eyes. The Rx gene family plays an important role in the establishment and/or proliferation of retinal progenitor cells.
脊椎动物眼睛的发育需要一系列步骤，包括前神经板的特化、视泡从腹侧前脑的外翻以及晶状体和视网膜的细胞分化。含同源异型框的基因，尤其是转录调节因子Pax6，在脊椎动物和无脊椎动物的眼睛形成中起关键作用。Pax6功能的突变会导致人类的无虹膜畸形和小鼠的小眼综合征等眼部畸形。Pax6在果蝇中的同源物无眼基因，对于无脊椎动物眼睛的正常发育也是必需的，其错误表达会导致果蝇中异位眼的形成。在这里，我们表明一个保守的脊椎动物同源异型框基因Rx对于正常眼睛发育至关重要，并且其错误表达会对眼睛形态产生深远影响。注射了合成Rx RNA的非洲爪蟾胚胎会发育出异位视网膜组织，并在神经视网膜中显示出过度增殖。携带该基因无效等位基因的小鼠胚胎不会形成视杯，因此不会发育出眼睛。Rx基因家族在视网膜祖细胞的建立和/或增殖中起重要作用。
