Transcriptional regulation of zebrafsh forebrain patterning

早期脊椎动物胚胎中的区域细胞身份部分是由一系列组织者创造的，这些组织者分泌信号分子并指定周围细胞的身份。前索前板是最前面的轴向中胚层，是前脑的关键组织者，并指定腹侧中线身份。缺乏前索前板的胚胎不表达腹侧前脑身份的标记，也不分离左右大脑半球。这一现象的影响是深远的，包括视网膜细胞迁移失败，导致单眼屈光不正。动物模型研究已经确定了两条信号通路--Sonic Hedgehog(Shh)和维甲酸(RA)--这两条信号通路对前索前板的规格和功能至关重要。

Regional cell identity in the early vertebrate embryo is created, in part, by a series of organizers, which secrete signaling molecules and specify the identity of surrounding cells. The prechordal plate is the anterior-most axial mesoderm and is a critical organizer that underlies the forebrain and specifies ventral midline identity. Embryos that lack a prechordal plate do not express markers of ventral forebrain identity or separate left and right cerebral hemispheres. The effects of this are profound, including failure of retinal cell migration, leading to the formation of a single cyclopic eye. Animal model studies have identified two signaling pathways - Sonic Hedgehog (Shh) and Retinoic Acid (RA) - that are critically important for specification and function of the prechordal plate.