Nutritional Cell Cycle and Differentiation Control

描述（由申请人提供）：拟议的研究侧重于维甲酸（RA）调节细胞生长和分化的复杂机制的一个方面。RA是一种膳食因子维生素a的活性代谢物，是幼鱼正常发育所必需的；胚胎形成过程中的形态发生体；和一种化学治疗剂调节肿瘤细胞的生长和分化。这些研究利用HL-60人类白血病细胞，这是一种未确定的造血前体细胞，可以经历髓系或单核细胞分化和氧化石墨烯阻滞。RA引起MAPK信号依赖的髓细胞分化和氧化石墨烯阻滞。这些研究将确定RA诱导的选定膜受体和适配器信号分子的表达对MAPK信号的意外激活和RA引起的基因表达变化的多样性的贡献。因此，他们关注两个基本的生物学问题：1)当MAPK信号通常被认为是有丝分裂发生的典型信号时，MAPK信号在ra诱导的生长停滞和分化中的意义是什么；2) RA引起生长停滞和分化所需的不同序列基因表达变化是如何发生的。我们的实验室以及其他研究人员使用差异显示、基于蛋白质组学的差异搜索或查询候选分子的组合进行了搜索，结果显示RA诱导了四种受体的表达，即c-FMS、BLR1、CD32和CD38，它们在特性上存在显著差异。因此，这些受体的下游信号结果可能是不同的，并调节不同基因集合的表达。然而，这些受体的一个共同特征是它们都与利用MAPK信号有关。RA还诱导了几种适配器分子的表达，特别是paxillin、SLP-76和dok。这些也与MAPK信号传导有关，在某些情况下明确与上述一些受体有关。目前的假设是，RA诱导细胞表面受体的表达，其信号传导受适配分子的调节，导致MAPK信号激活和相应的蛋白表达变化，最终导致氧化石墨烯阻滞和分化。受体和转接器的不同组合直接改变了不同蛋白群的表达，每种组合都会导致RA的总变化。实验目的是通过单独或联合表达这些受体和适配器，以确定它们刺激MAPK信号传导和引起基因表达变化的能力，从而导致ra诱导的总变化，并测试它们诱导表达对ra诱导的分化或GO阻滞的功能意义。

DESCRIPTION (provided by applicant): The proposed studies focus on one aspect of the complex mechanism by which retinoic acid (RA) regulates cell growth and differentiation. RA is the active metabolite of a dietary factor, vitamin A, necessary for proper development in juveniles; a morphogen during embryogenesis; and a chemotherapeutic agent regulating growth and differentiation of neoplastic cells. The studies utilize HL-60 human leukemia cells, an uncommitted hematopoietic precursor cell that can undergo myeloid or monocytic differentiation and GO arrest. RA causes MAPK signaling dependent myeloid differentiation and GO arrest of these cells. The studies will determine the contribution of RA-induced expression of selected membrane receptors and adapter signaling molecules to the unanticipated activation of MAPK signaling and to the diversity of gene expression changes caused by RA. They thus focus on two basic biological questions: 1) what is the significance of MAPK signaling in Ra-induced growth arrest and differentiation when such signaling is usually considered the prototypical signal for mitogenesis; 2) how are the diverse sequential gene expression changes needed to evoke growth arrest and differentiation generated by RA. Searches by our laboratory, as well as others, using a combination of differential display, a proteomics based differential search, or querying candidate molecules revealed that RA induces the expression of four receptors, c-FMS, BLR1, CD32, and CD38, which differ significantly in character. The downstream signaling consequences of these receptors are thus likely to differ and regulate the expression of different ensembles of genes. However, a common feature of these receptors is that all have been implicated with utilizing MAPK signaling. RA also induces the expression of several adapter molecules, in particular paxillin, SLP-76, and dok. These, too, have been connected with MAPK signaling and in some cases explicitly to some of the aforementioned receptors. The working hypothesis is that RA induces the expression of cell surface receptors, whose signaling is regulated by adapter molecules, resulting in MAPK signal activation and consequential changes in protein expression ultimately leading to GO arrest and differentiation. Different combinations of receptors and adapters then direct changes in the expression of different ensembles of proteins, each combination contributing to the total changes attributed to RA. The experimental aims are to ectopically express these receptors and adapters, singly and in combination, to determine their ability to stimulate MAPK signaling and cause gene expression changes that contribute to the total RA-induced changes, and to test the functional significance of their induced expression to RA-induced differentiation or GO arrest.