TRANSCRIPTIONAL REGULATION OF EMBRYONIC CARDIOGENESIS

我们集中研究了小鼠心脏特异性同源结构域基因Nkappax 2 -5 这对胚胎心脏的形成起着重要作用。我们展示 Nkappax 2 -5与其他蛋白质形成组合结合复合物， 转录因子，如对心脏，骨骼， 和平滑肌组织。加塔-4与这些因素协同行动， 因子刺激的心肌肌动蛋白基因之间的几个心脏特异性 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定型过程中表达， 与Nkappax 2 -5不同，Nkappax 2 -8在心管 循环，直到它再次出现在流入道和流出道 以及与胸腺形成有关的咽弓。Nkappax 2 -8 与被认为与癌症相关的基因有惊人的相似性， 迪乔治综合征在拟议的研究中，我们试图确定 Nkx 2 -8调节作用以及Nkx 2 -5和Nkx 2 -8是否起作用 在驱动心脏细胞分化和形态发生中的冗余作用。 该提案的具体目标是： Nkappax 2 -8在小鼠心脏形态发生中空间表达到 定义Nkappax 2 -5的功能性蛋白质结构域区域， 与加塔、SRF等调控因子的关联和相互作用。 表征编码Nkappax 2 -5的鼠基因组基因座，以鉴定 顺式作用序列和反式作用因子负责高 Nkappax 2 -5在原始心肌中的水平表达和通过肽 生长因子探讨同源重组的后果 Nkappax 2 -5、Nkappax 2 -8、SRF和加塔4的DNA敲除及其相互作用 作为一种方法来测试他们的组合调控作用，在早期 胚胎心脏形成为了表征纯合子的表型， Nkappax 2 -8缺陷突变体以及Nkappax 2 -8是否在CATCH-1中起作用。 22和DiGeorge综合征？为了开发一种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在肿瘤发生中的作用 对心脏发育的影响我们相信，定义分子基础 心肌的建立和维持 差异化最终可能会导致更好的理解 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.