Molecular Determinants of Chromosome Transmission and Cell Cycle Regulation

我们之前已经证明，酿酒葡萄球菌的SPT4有助于进化上保守的着丝粒组蛋白H3变体（CenH3） Cse4p的适当定位。本实验室的主要研究目标是研究调节Cse4p及其相互作用伙伴（Scm3p和Histone H4）介导忠实染色体分离的分子机制。我们研究了Cse4p定位的机制，并确定了Cse4p的错误定位和组蛋白化学计量的改变导致染色体传播缺陷。我们的研究还表明，在酵母和人类系统中，过表达Scm3p及其人类同源物HJURP会导致基因组不稳定。我们研究了染色质修饰剂和着丝点蛋白的翻译后修饰对CenH3染色质组装/功能的影响。我们的研究结果表明，着丝粒组蛋白H4的低乙酰化状态是染色体忠实分离的关键。我们最近在酿酒酵母中关于Cse4p定位和组蛋白剂量的研究结果与s.p ombe一致，表明其潜在机制是守恒的。我们还利用大约6000株芽殖酵母的杂合双倍体菌株进行了基因组宽筛选，以确定单倍体不足以维持染色体稳定性的基因。这些分析的结果使我们能够定义维持酵母和人类基因组稳定性的进化保守途径。我们对酿酒酵母忠实染色体传播的分子决定因素的研究将有助于我们了解人类的类似过程及其对人类疾病的影响。我们的实验室在利用传统的遗传、生化和细胞生物学方法以及高通量基因组分析研究项目方面具有独特的优势。我们使用一系列基因缺失菌株和一个集落挑选机器人来识别可能的癌症药物靶点，并通过合成基因组分析（SGA）进行遗传筛选，该分析由查理·布恩（多伦多大学）的实验室开发。

We had previously shown that S. cerevisiae SPT4 contributes to the proper localization of evolutionarily conserved centromeric histone H3 variant (CenH3) Cse4p. The major research goal of our laboratory is to investigate the molecular mechanisms that regulate the function of Cse4p and its interacting partners (Scm3p and Histone H4) to mediate faithful chromosome segregation. We investigated the mechanism of Cse4p localization and have established that mislocalization of Cse4p and altered histone stoichiometry lead to defects in chromosome transmission. Our studies have also shown that overexpression Scm3p and its human homolog HJURP leads to genome instability in yeast and human systems. We examined the effect of chromatin modifiers and post-translational modification of kinetochore proteins on the assembly/function of CenH3 chromatin. Our results showed that hypoacetylation state of centromeric histone H4 is critical for faithful chromosome segregation. Our recent results with Cse4p localization and histone dosage in S. cerevisiae are consistent with those in S. pombe, suggesting conservation of the underlying mechanisms. We have also done genome wide screens using heterozygous dipolid strain collection of about 6000 strains of budding yeast to define genes that are haploinsufficient for chromosome stability. Results from these analyses has allowed us to define evolutionarily conserved pathways that maintain genome stability in yeast and humans. Our research on the molecular determinants of faithful chromosome transmission in S. cerevisiae will help us understand analogous processes in humans and their implications in human disease. Our laboratory is uniquely poised to utilize conventional genetic, biochemical, and cell biology approaches, as well as high-throughput genomic analysis for our research projects. We use an array of gene-deletion strains and a colony-picking robot for the identification of possible cancer drug targets and also for genetic screens by synthetic genome analysis (SGA), developed in the laboratory of Charlie Boone (University of Toronto).