MOLECULAR GENETICS OF MAMMALIAN BARREN (BRRN 1)

描述：研究拟分析人类和小鼠同源物 最近描述的果蝇蛋白质贫瘠。 在果蝇中， 是色臂分离所必需的，并已被证明与 topo II并在体外调节其活性。 贝尔蒙特博士和他的 我的同事们打算检验一个假设，即贫瘠的功能是保守的， 并且其在哺乳动物染色单体臂分离中的活性类似于 在果蝇中观察到的。 他们已经部分鉴定了这个基因 编码人类不育（BRRN-1），并确定了其他成员， 人类和小鼠基因组中假定的不育基因家族。 调查人员 建议采用几种策略，以更好地了解 born-1及其在人类细胞中的作用机制。 第一种方法 将检测barn-1在细胞中的表达和亚细胞定位 周期 他们还将分析罗伯茨综合征中的barn-1表达 细胞，一种人类突变，似乎涉及一个特定的缺陷， 染色单体臂分离。 然后他们会评估潜在的贫瘠 与拓扑异构酶II和SMC的哺乳动物同系物的相互作用 （结构维持染色体）蛋白，XCAP-C和XCAP-E。 最终 该策略将在培养ES中采用小鼠mbrrn-1的靶向失活 细胞 将测试简单和诱导型失活构建体。 根据这些实验的结果， 将尝试纯合突变小鼠。 小鼠的类似突变体 还将评估lodestar样解旋酶基因。 在北极星果蝇中 突变体似乎影响染色单体臂分离。 遗传相互作用和 将检查对空表达的影响。 拟议的研究应 提供有关topo II调节及其 参与哺乳动物细胞的后期过程。 阐明 这些事件对理解染色体有着更广泛的意义 染色体不分离和其他人类疾病 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.