Control of Cell Proliferation by Runx Proteins

描述（由申请人提供）：Runt结构域（Runx）转录因子是动物发育的关键调控因子。三种哺乳动物Runx基因中的每一种都是主要器官系统发育所必需的，而在人类中，这三种基因都与细胞增殖失控引起的疾病有关。RUNXl是最终造血所必需的，是人类白血病中最常见的突变基因；RUNX2是成骨所必需的，其单倍体不足导致锁骨颅内发育不良；RUNX3是背根神经节的神经发育和胃发育中细胞增殖的控制所必需的，在人胃癌中经常被删除或沉默。这项拨款的目的是确定Runx蛋白在发育过程中控制细胞增殖的分子机制。为此，我们正在使用海胆胚胎发生作为一个简化的模型系统。与拥有3个Runx基因的哺乳动物不同，海胆只有一个Runx基因（SpRunt）。与其他Runx蛋白一样，SpRunt与β亚基（spcbf - β）形成异源二聚体。我们的初步数据表明，SpRunt是胚胎发生过程中正常细胞增殖程序和细胞周期蛋白d转录激活所必需的。本资助的具体目的是：(1)进一步确定SpRunt在细胞增殖中的作用；(2)确定SpRunt如何在cyclinD顺式调控系统中发挥作用；(3)研究SpRunt活性如何受到其异二聚体伴侣spcbfβ的发育调节。这些目标将通过利用海胆胚胎作为细胞生理、基因调控和发育的生化和分子分析系统的优势，以及紫癜海胆基因组序列的可用性来实现，这将极大地促进基因的顺式调控分析和纯化蛋白的质谱鉴定。

DESCRIPTION (provided by applicant): Runt domain (Runx) transcription factors are key regulators of animal development. Each of the three mammalian Runx genes is required for the development of a major organ system, and in humans all three are associated with disease caused by uncontrolled cell proliferation. RUNXl is required for definitive hematopoiesis, and is the most frequently mutated gene in human leukemia; RUNX2 is required for osteogenesis, and its haploinsufficiency causes cleidocranial dysplasia; and RUNX3 is required for neural development in the dorsal root ganglia and for control of cell proliferation in the developing stomach, and is frequently deleted or silenced in human stomach cancer. The purpose of this grant is to define the molecular mechanisms through which Runx proteins control cell proliferation during development. Toward this end we are using sea urchin embryogenesis as a simplified model system. Unlike mammals, which have 3 Runx genes, the sea urchin Strongylocentrotus purpuratus has only a single Runx gene (SpRunt). As is the case with other Runx proteins, SpRunt forms a heterodimer with a beta subunit (SpCBFbeta). Our preliminary data show that SpRunt is required for the normal program of cell proliferation during embryogenesis and for the transcriptional activation of cyclin D. The specific aims of this grant are: (1) to further define the roles of SpRunt in cell proliferation; (2) to determine how SpRunt functions within the context of the cyclinD cis-regulatory system; and (3) to investigate how SpRunt activity is developmentally regulated by its heterodimeric partner, SpCBFbeta. These aims will be achieved by exploiting the strengths of the sea urchin embryo as a system for biochemical and molecular analyses of cell physiology, gene regulation, and development, and the availability of the S. purpuratus genome sequence, which will greatly facilitate both the cis-regulatory analysis of genes and the identification of purified proteins by mass spectrometry.