TRANSCRIPTIONAL REGULATION OF EMBRYONIC CARDIOGENESIS

我们重点研究了小鼠心脏特异的同源结构域基因Nkappax2-5 这对胚胎心脏的形成起到了重要作用。我们展示了 Nkappax2-5与其他化合物形成结合络合物 转录因子，如血清对心脏、骨骼、 和平滑的肌肉组织。在这些因素的配合下，GATA-4 因子刺激的心脏肌动蛋白基因在几种特定心脏之间 交易因素。我们分离出了一个新的Nkappax家族成员Nkx-28， 它也在非常早期的心脏细胞承诺中表达，但是 与Nkappax2-5不同，Nkappax2-8作为心管下调 经过循环，直到它再次出现在流入和流出区域 以及与胸腺形成相关的咽弓。Nkappax2-8 显示出惊人的相似性，与被认为与 迪乔治综合征。在拟议的研究中，我们试图确定 Nkappax2-8的调节作用及Nkx2-5和Nkx2-8是否发挥作用 在驱动心脏细胞分化和形态发生中的多余作用。 该提案的具体目标是：确定时间和 Nkappax2-8在小鼠心脏形态发生过程中的空间表达至 确定Nkappax2-5的功能蛋白结构域 与GATA、SRF和其他监管因素的关联和相互作用。 鉴定编码Nkappax2-5的小鼠基因组座位 高致病基因的顺式作用序列和反式作用因素 Nkappax2-5在原始心肌和多肽中的水平表达 增长因素。研究同源重组的后果 Nkappax2-5、Nkappax2-8、SRF和GATA 4的DNA敲除及其相互作用 十字架作为一种在早期测试其组合调节作用的方法 胚胎心脏的形成。纯合子的表型特征 Nkappax2-8缺陷突变体以及Nkappax2-8是否在捕获性肺炎中起作用 22岁和迪乔治综合征？开发Nkappax-2-5驱动的心脏- 基于cre-lox重组酶策略的特异性基因敲除系统 研究SRF和其他辅助转录因子的作用 关于心脏发育的研究。我们认为，定义分子基础 建立和维持心肌的基础 差异化可能最终会导致对 心血管疾病。

We have focused on a murine cardiac specific homeodomain gene, Nkappax2-5 which is instrumental in the patterning of the embryonic heart. We showed that Nkappax2-5 forms combinatorial binding complexes with other transcription factors, such as serum response factor to cardiac, skeletal, and smooth muscle tissues. Acting in concert with these factors, GATA-4 factor stimulated cardiac actin gene between several cardiac specified transacting factors. We isolated a new Nkappax family member, Nkx-28, which is also expressed during very early heart cell commitment, but unlike Nkappax2-5, Nkappax2-8 was down regulated as the heart tube underwent looping, until it reappeared in the inflow and outflow tracts and in the pharyngeal arches associated with thymus formation. Nkappax2-8 displayed striking similarities with genes thought to be associated with DiGeorge's Syndrome. In the proposed studies, we are trying to determine the regulatory role of Nkappax2-8 and whether Nkx2-5 and Nkx2-8 play redundant roles in driving heart cell differentiation and morphogenesis. The Specific Aims of the proposal are: To determine the temporal and spatial expression of Nkappax2-8 during cardiac morphogenesis in mouse. To define functional protein domainal regions of Nkappax2-5 required for association and interaction with GATA, SRF and other regulatory factors. To characterize the murine genomic locus encoding Nkappax2-5 to identify the cis-acting sequences and trans-acting factors responsible for the high level expression of Nkappax2-5 in primitive myocardium and by peptide growth factors. To investigate the consequence of homologous recombinant DNA knockouts of Nkappax2-5, Nkappax2-8, SRF, and GATA 4 and their inter crosses as a way to test their combinatorial regulatory roles in early embryonic heart formation. To characterize the phenotype of homozygous Nkappax2-8 defective mutants and whether Nkappax2-8 plays a role in CATCH- 22 and DiGeorge syndrome? To develop an Nkappax-2-5 driven cardiac- specific gene knock-out system based on the cre-lox recombinase strategy to investigate the role of SRF and other accessory transcription factors on cardiac development. We believe that defining the molecular basis underlying the establishment and maintenance of cardiac muscle differentiation may eventually lead to an improved understanding of cardiovascular disease.