Neuman T, Keen A, Zuber M X, Kristjansson G I, Gruss P, Nornes H O
Department of Anatomy and Neurobiology, Colorado State University, Fort Collins 80523.
Dev Biol. 1993 Nov;160(1):186-95. doi: 10.1006/dbio.1993.1297.
Id-like helix-loop-helix (HLH) proteins, which lack a basic DNA binding domain, have been suggested to serve as general inhibitors of differentiation. We present data that Id2 is expressed in specific cell types during neurogenesis and in the adult. At early stages of neurogenesis, Id2 is expressed in the ventricular zone of neuroepithelium. After the first neuronal populations are born, the expression of Id2 is down regulated in neuroepithelial cells and continues to be high in Purkinje cells of the cerebellum, in mitral cells of the olfactory bulb, and in layers 2, 3, and 5 of the cerebral cortex. In neuronally differentiating cell lines, the Id2 expression is up regulated (PCC7), down regulated (NG108), or unchanged (N18) during differentiation. Analyses of promoter sequences of the Id2 gene identify the region which is responsible for the down regulation of transcription during neuronal differentiation. Our data indicate that Id2 has different functions in different cell types during neurogenesis.
缺乏基本DNA结合结构域的类Id螺旋-环-螺旋（HLH）蛋白被认为可作为分化的一般抑制剂。我们提供的数据表明，Id2在神经发生过程中的特定细胞类型以及成体中均有表达。在神经发生的早期阶段，Id2在神经上皮的脑室区表达。第一批神经元群体诞生后，Id2在神经上皮细胞中的表达下调，而在小脑的浦肯野细胞、嗅球的二尖瓣细胞以及大脑皮层的第2、3和5层中持续高表达。在神经元分化的细胞系中，Id2的表达在分化过程中上调（PCC7）、下调（NG108）或不变（N18）。对Id2基因启动子序列的分析确定了在神经元分化过程中负责转录下调的区域。我们的数据表明，Id2在神经发生过程中的不同细胞类型中具有不同功能。
