Integrated MAP Kinase Signaling In Cell Differentiation

本提案的目的是定义控制神经元分化的信号转导通路。我们对培养的PC12嗜铬细胞瘤细胞的研究表明，细胞外信号调节激酶（ERK）和cJun N-末端激酶（JNK）家族的分裂原活化蛋白（MAP） MAP激酶与特异性CREB和Jun家族成员在神经元特异性基因诱导中的整合。PC12嗜铬细胞瘤细胞是控制神经分化的神经生长因子（NGF）依赖信号通路的建立模型。我们最近建立了多能小鼠胚胎发育的体外神经元分化条件，所产生的神经元高度代表了它们在体内产生的对应体。编码MAP激酶成分和转录因子靶点的基因被纯合删除的小鼠胚胎干细胞产生神经元的能力，为神经元分化的信号转导提供了一种强有力的遗传途径。我们假设，不同的MAP激酶信号通路及其特定的转录因子靶点的整合作为一个分子开关，诱导获得神经表型所需的多个基因。为了验证这一假设，我们将完成以下具体目标：鉴定PC12细胞和ES细胞神经元分化过程中诱导NFLC基因的信号通路。目标2。定义神经元分化中的调控因素。目标3。定义调控NFLC启动子的信号通路和转录因子在PC12和ES细胞中作为参与诱导多个神经特异性基因的分子开关的作用。MAP激酶已经在有丝分裂发生的背景下被广泛分析，但没有分化。这些目标的完成将阐明这些信号通路调节细胞分化所需基因转录的机制，这是一个研究相对不足的研究领域。

The objective of this proposal is to define signal transduction pathways that control neuronal differentiation. Our studies with cultured PC12 pheochromocytoma cells, an established model for analysis of nerve growth factor (NGF)- dependent signaling pathways that control neural differentiation, indicate the integration of the extracellular signal-regulated kinase (ERK) and cJun N- terminal kinase (JNK) families of mitogens-activated protein (MAP) MAP kinases and specific CREB and Jun family members in neuron-specific gene induction. We have recently established the conditions for in vitro neuronal differentiation of multipotent murine embryonic development and the resulting neurons are highly representative of their in vivo-generated counterparts. The ability to generate neurons for ES cells derived from mice in which genes encoding MAP kinase components and transcription factor targets are homozygously deleted provides a powerful genetic approach to signal transduction of neuronal differentiation. We hypothesize that integration of distinct MAP kinase signaling pathways and their specific transcription factor targets serve as a molecular switch to induce multiple genes required for acquisition of the neural phenotype. To test this hypothesis, we will complete these specific aims: Aim 1. Identify the signaling pathways that induce the NFLC gene during neuronal differentiation of PC12 cells and ES cells. Aim 2. Define the regulatory elements within the neuronal differentiation. Aim 3. Define the role of the signal pathways and transcription factors that regulate the NFLC promoter as a molecular switch involved in the induction of multiple neural-specific genes in PC12 and ES cells. MAP kinases have been extensively analyzed in the context of mitogenesis, but not differentiation. Completion of these aims will elucidate the mechanism by which these signal pathways can regulate the transcription of genes required for cell differentiation, a comparatively understudied research area.