ROLE OF TFII-I IN CRANIOFACIAL DEVELOPMENT

描述(申请人提供)：颅面部相关出生缺陷占所有先天畸形的三分之一。神经脊细胞(NCC)的缺陷导致了这些疾病的大部分；然而，涉及颅面形态发生的信号通路却知之甚少。因此，了解神经脊发育的分子机制对于了解人类颅面部疾病是必要的。我们的长期目标是确定指导NCC形态发生的调控途径。本应用的目的是确定TFII-I转录因子在头面部发育中的分子和遗传作用。编码这种蛋白的Gtf2i等位基因的缺失会导致小鼠的头面部缺陷。TFII-I通过与组蛋白脱乙酰酶和Smad2的相互作用调节靶基因的转录，并在神经脊来源的组织中表达。我们推测TFII-I的作用之一是控制对神经脊形态发生至关重要的信号级联反应。因此，我们建议对Gtf2i进行深入分析，以了解其在神经脊发育中的作用。首先，将分析突变胚胎中导致头面部缺陷的分子和细胞变化。其次，将利用基因芯片和染色质免疫沉淀分析鉴定一组颅脑NCC中受TFII-I调控的下游靶基因。第三，在条件Cre/loxP重组系统中，Gtf2i等位基因在NCC谱系中将被废除。这项研究的结果将使我们能够确定参与神经脊源性结构形态发生的依赖于TFII-L的基因和信号通路。这些研究将有助于更好地了解颅面遗传途径和人类出生缺陷的发病机制。

DESCRIPTION (provided by applicant): Craniofacial related birth defects account for 1/3rd of all congenital anomalies. Defects in neural crest cells (NCC) cause most of these disorders; however, the signaling pathways involved in craniofacial morphogenesis are poorly understood. Therefore, knowledge of the molecular mechanisms of neural crest development is necessary to understand human craniofacial disorders. Our long-term goal is to identify the regulatory pathways that instruct NCC morphogenesis. The objective of this application is to determine the molecular and genetic role of the TFII-I transcription factor in craniofacial development. Deletion of the Gtf2i allele, which encodes this protein causes craniofacial defects in mice. TFII-I regulates the transcription of target genes via interactions with histone deacetylases and Smad2 and is expressed in neural crest-derived tissues. We hypothesize that 1 of the roles of TFII-I is to control signaling cascades critical for neural crest morphogenesis. We, therefore, propose an in depth analysis of Gtf2i to understand its role during neural crest development. First, molecular and cellular changes underlying craniofacial defects will be analyzed in mutant embryos. Second, a set of downstream target genes regulated by TFII-I in cranial NCC will be identified using microarray and chromatin immunoprecipitation analysis. Third, the Gtf2i allele will be abrogated in the NCC lineage with the conditional Cre/LoxP recombination system. The outcome of the proposed research will allow us to identify the TFII-l-dependent genes and signaling pathways involved in the morphogenesis of neural crest-derived structures. These studies will provide a better understanding of craniofacial genetic pathways and pathogenesis of human birth defects.