Fernandez A S, Pieau C, Repérant J, Boncinelli E, Wassef M
CNRS URA 1414, Equipe Régionalisation Nerveuse, Ecole Normale Supérieure, 46, rue d'Ulm 75230 PARIS Cedex 05 France.
Development. 1998 Jun;125(11):2099-111. doi: 10.1242/dev.125.11.2099.
Homologies between vertebrate forebrain subdivisions are still uncertain. In particular the identification of homologs of the mammalian neocortex or the dorsal ventricular ridge (DVR) of birds and reptiles is still a matter of dispute. To get insight about the organization of the primordia of the main telencephalic subdivisions along the anteroposterior axis of the neural tube, a fate map of the dorsal prosencephalon was obtained in avian chimeras at the 8- to 9-somite stage. At this stage, the primordia of the pallium, DVR and striatum were located on the dorsal aspect of the prosencephalon and ordered caudorostrally along the longitudinal axis of the brain. Expression of homeobox-containing genes of the Emx, Dlx and Pax families were used as markers of anteroposterior developmental subdivisions of the forebrain in mouse, chick, turtle and frog. Their expression domains delineated three main telencephalic subdivisions in all species at the onset of neurogenesis: the pallial, intermediate and striatal neuroepithelial domains. The fate of the intermediate subdivisions diverged, however, between species at later stages of development. Homologies between forebrain subdivisions are proposed based on the conservation and divergence of these gene expression patterns.
脊椎动物前脑各亚区之间的同源性仍不明确。特别是，哺乳动物新皮层或鸟类和爬行动物背侧室嵴（DVR）的同源物的鉴定仍存在争议。为了深入了解主要端脑亚区原基沿神经管前后轴的组织情况，在8至9体节期的鸟类嵌合体中获得了背侧前脑的命运图谱。在此阶段，大脑皮层、DVR和纹状体的原基位于前脑的背侧，并沿脑的纵轴从尾端向头端排列。Emx、Dlx和Pax家族含同源框基因的表达被用作小鼠、鸡、龟和蛙前脑前后发育亚区的标志物。在神经发生开始时，它们的表达域在所有物种中划定了三个主要的端脑亚区：大脑皮层、中间和纹状体神经上皮域。然而，在发育后期，中间亚区的命运在不同物种之间出现了分歧。基于这些基因表达模式的保守性和差异性，提出了前脑亚区之间的同源性。
