DEVELOPMENTAL CONTROL OF GNRH EXPRESSION BY POU PROTEINS

描述(改编自《调查者摘要》)：POU同源域 蛋白质是在分化中起作用的转录因子，并且 神经内分泌基因的发育控制。促性腺激素释放激素基因是 在下丘脑神经元的一个子集中表达，其独特之处在于 其表型在发育过程中的可塑性。GnRH神经元表型为 随着细胞完成早期增殖而迅速获得 胚胎发生，然后在发情期间经历丢失和恢复 周而复始。这引发了这样一个问题：POU蛋白是否在 神经元GnRH基因表达的调控。波域家族成员， 从GT1-7神经细胞中克隆了SCIP和BRN-4。生理学 SCIP或BRN-4与GnRH共定位显示有意义 活体中的神经元。SCIP和BRN-4的过量生产被证明抑制了或 分别激活GnRH启动子活性，需要两个直接结合 DNA和蛋白质之间的相互作用。这项建议有4个具体目标： 目的1-检测SCIP和BRN-4在体内GnRH神经元中的表达； 目标2-通过靶向确定SCIP对GnRH的调节的相关性 SCIP在转基因动物中的过表达及其拮抗作用 定位GnRH启动子的顺式作用元件 被SCIP抑制，被BRN-4及其蛋白伴侣激活； 4-确定并克隆指导SCIP和BRN-4作用的蛋白质伙伴 在GnRH上。这些研究将共同定义生理作用和 POU蛋白调控和GnRH基因表达的细胞机制。

DESCRIPTION (Adapted from the Investigator's Abstract): POU homeodomain proteins are transcription factors that play a role in differentiation, and the developmental control of neuroendocrine genes. The GnRH gene is expressed in a subset of hypothalamic neurons and is unique in its plasticity of its phenotype across development. GnRH neuronal phenotype is acquired rapidly as cells complete an early proliferation during embryogenesis, and then undergo loss and reinstatement during the estrous cycle. This led to the question whether POU proteins play a role in the control of neuronal GnRH gene expression. The POU-domain family members, SCIP and Brn-4 were cloned from GT1-7 neuronal cells. Physiological significance was shown by colocalization of SCIP or Brn-4 with GnRH in neurons in vivo. Overproduction of SCIP and Brn-4 was shown to repress or activate GnRH promoter activity, respectively, requiring both direct binding to DNA and protein-protein interactions. This proposal has 4 specific aims: Aim 1-To assess the expression of SCIP and Brn-4 in GnRH neurons in vivo; Aim 2-define the relevance of SCIP modulation of GnRH by targeted overexpression and antagonism of SCIP in transgenic animal; Aim 3-precisely localize the cis-acting elements of the GnRH promoter that mediate repression by SCIP and activation by Brn-4 and their protein partners; 4-identify and clone the protein partners that direct SCIP and Brn-4 action on GnRH. Together these studies will define the physiological role and cellular mechanisms of POU protein control and GnRH gene expression.