MOLECULAR GENETICS OF MAMMALIAN BARREN (BRRN 1)

描述：建议进行研究以分析人类和老鼠的同源基因 最近被描述的果蝇蛋白质不育。在果蝇中，贫瘠 是彩色臂分离所必需的，并且已被证明与 Topo II并在体外调节其活性。贝尔蒙特博士和他的 同事们打算测试不育功能是保守的这一假设 它在哺乳动物染色单体臂分离中的活性与 这是在果蝇身上观察到的。他们已经部分确定了这种基因的特征。 编码人类不育基因(BRRN-1)，并已识别出 人类和小鼠基因组中可能存在的不育基因家族。调查人员 建议采用几种策略来更好地理解 Branren-1及其在人类细胞中的作用机制。第一种方法 将检测Branren-1在细胞中的表达和亚细胞定位 周而复始。他们还将分析Barren-1在罗伯茨综合征中的表达 细胞，这是一种人类突变，似乎涉及到 染色单体臂分离。然后他们将评估潜在的不毛之地 与拓扑异构酶II的相互作用以及SMC的哺乳动物同源物 (结构维持染色体)蛋白质，XCAP-C和XCAP-E。决赛 策略将在培养的ES中使用靶向灭活小鼠mbrrn-1 细胞。简单的和可诱导的失活结构都将被测试。 根据这些实验的结果，产生杂合子和 纯合子突变小鼠将被尝试。小鼠的相似突变体 还将评估类似于LODESTAR的解旋酶基因。在果蝇中 突变体似乎影响染色单体的臂分离。遗传交互作用和 将考察对不育表达的影响。建议的研究应 就TOPO II和ITS的监管提供有价值的信息 参与哺乳动物细胞的后期过程。澄清： 这些事件对于理解染色体有更广泛的意义。 不分离和其他与染色体相关的人类疾病 不稳定。

DESCRIPTION: Studies are proposed to analyze the human and mouse homologues of the recently described Drosophila protein barren. In Drosophila, barren is required for chromatic arm separation and has been shown to interact with topo II and to modulate its activity in vitro. Dr. Belmont and his colleagues intend to test the hypothesis that barren function is conserved and that its activity in mammalian chromatid arm separation is similar to that observed in Drosophila. They have partially characterized the gene encoding human barren (BRRN-1) and have identified other members of a putative barren gene family in human and mouse genomes. The investigators propose to employ several strategies to better understand the function of barren-1 and its mechanism of action in human cells. The first approach will examine barren-1 expression and subcellular localization in the cell cycle. They will also analyze barren-1 expression in Roberts syndrome cells, a human mutation which appears to involve a specific defect in chromatid arm separation. They will then evaluate potential barren interaction with topoisomerase II, and mammalian homologues of the SMC (structural maintenance chromosomes) proteins, XCAP-C and XCAP-E. The final strategy will employ targeted inactivation of mouse mbrrn-1 in cultured ES cells. Both simple and inducible inactivation constructs will be tested. Depending on the outcome of these experiments production heterozygous and homozygous mutant mice will be attempted. Similar mutants of the mouse lodestar-like helicase gene will also be evaluated. In Drosophila lodestar mutants appear to affect chromatid arm separation. Genetic interaction and effects on barren expression will be examined. The proposed studies should yield valuable information on the regulation of topo II and its participation in the anaphase process of mammalian cells. Elucidation of these events has broader implications for understanding chromosome non-disjunction and other human disorders associated with chromosome instability.