REGULATION OF MOUSE ES CELL DIFFERENTIATION INTO NEURONS BY HOXA1

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 该项目的长期目标是阐明和表征HoxA1转录因子引导胚胎干细胞分化为神经元的分子机制。细胞和组织中HoxA1基因的表达可以被维生素A的衍生物维甲酸(RA)激活。在小鼠中，HoxA1基因的两个等位基因的失活都会导致许多发育缺陷，包括后脑缺陷和异常的头骨骨化，最终导致新生儿死亡。在人类中，HOXA1基因的截断突变与自闭症易感性有关。本项目将研究HoxA1在RA诱导悬浮培养的小鼠胚胎干细胞(ES)分化为类胚体(EBS)过程中的功能。由于RA是HoxA1基因表达的直接诱导者，也是ES细胞分化的诱导者，我们假设HoxA1的作用是通过抑制内胚层和/或中胚层细胞系来促进神经细胞的分化。我们还假设RARb的特异性激活可能导致小鼠ES细胞的内胚层分化和抑制神经发生。为了验证这一假设，我们首先利用抗体芯片检测了RARb2激动剂AC55649对蛋白质表达的影响。作为RARb2处理的结果，我们观察到用阵列检测到的大约40个蛋白质(在224个蛋白质中)增加了2倍或更多，其中大多数在Path Architect检查后被发现与AP1/c-Jun通路有关。这些研究的结果可能导致在培养中产生同质细胞群体的新的分化策略。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The long-term goal of this project is to elucidate and characterize the molecular mechanism by which the Hoxa1 transcription factor directs the differentiation of embryonic stem cells into neurons. Expression of the Hoxa1 gene in cells and tissues can be activated by retinoic acid (RA), a derivative of vitamin A. Inactivation of both alleles of the Hoxa1 gene in mice results in numerous developmental defects, including hindbrain deficiencies and abnormal skull ossification, and ultimately, in neonatal death. In humans, truncating mutations of the HOXA1 gene have been associated to autism susceptibility. This project will characterize the function of Hoxa1 during the RA-induced differentiation of mouse embryonic stem (ES) cells grown in suspension as embryoid bodies (EBs). Because RA is a direct inducer of Hoxa1 gene expression and is also an inducer of ES cell differentiation, we hypothesize that the role of Hoxa1 is to promote neuronal cell differentiation by repressing endodermal and/or mesodermal cell lineages. We also hypothesize that the specific activation of RARb may lead to endodermal differentiation and repression of neurogenesis in mouse ES cells. To test this hypothesis, we first examined the effect of the RARb2 agonist AC55649 on protein expression by employing antibody microarrays. As a consequence of RARb2 treatment, we observed that about 40 (out of 224) proteins examined with the array were increased by 2-fold or more, and of these, most were found to be related to the Ap1/c-Jun pathway after Pathway Architect examination. The results obtained from these studies may result in novel differentiation strategies for the generation in culture of homogeneous cell populations.