Fedtsova N, Turner E E
Department of Psychiatry, University of California at San Diego, 92093-0603, USA.
Dev Biol. 1997 Oct 1;190(1):18-31. doi: 10.1006/dbio.1997.8691.
Brn-3.0, a POU-domain transcription factor, is expressed in specific postmitotic neurons in the dorsal part of the neural tube which are among the first spinal cord neurons to appear in development. In the mature spinal cord, the Brn-3.0 cells form a numerous population of scattered neurons in the intermediate spinal gray. Ablation of the notochord in chick embryos extends the domain of Brn-3.0 expression into the ventral neural tube, while ectopic grafts of notochord tissue suppress Brn-3.0 expression. The notochord effects on Brn-3.0 expression are reproduced in vivo by the implantation of a local source of recombinant Shh protein. The down-regulation of Brn-3.0 expression in the dorsal spinal cord by the notochord and Shh contrasts with the known inductive effects of these ventral signals on the approximately simultaneous development of the spinal motor neurons. In cultured explants of neural plate from the region of the presumptive spinal cord, Brn-3.0 neurons develop in the absence of surface ectoderm and ventral midline tissue, suggesting that the Brn-3.0 phenotype may represent a "default" developmental pathway for early spinal cord neurons. Together these results advance the understanding of the mechanism of the generation of neuronal diversity in the developing vertebrate CNS.
Brn-3.0是一种POU结构域转录因子，在神经管背侧特定的有丝分裂后神经元中表达，这些神经元是发育过程中最早出现的脊髓神经元之一。在成熟脊髓中，Brn-3.0细胞在脊髓灰质中间形成大量分散的神经元群体。鸡胚脊索的切除将Brn-3.0的表达区域扩展到腹侧神经管，而脊索组织的异位移植则抑制Brn-3.0的表达。通过植入局部重组Shh蛋白源，脊索对Brn-3.0表达的影响在体内得以重现。脊索和Shh对脊髓背侧Brn-3.0表达的下调，与这些腹侧信号对脊髓运动神经元大致同时发育的已知诱导作用形成对比。在来自假定脊髓区域的神经板培养外植体中，Brn-3.0神经元在没有表面外胚层和腹侧中线组织的情况下发育，这表明Brn-3.0表型可能代表早期脊髓神经元的一种“默认”发育途径。这些结果共同推进了对发育中的脊椎动物中枢神经系统中神经元多样性产生机制的理解。
