Molecular Determinants of Chromosome Transmission and Cell Cycle Regulation

我们先前已经证明，酿酒酵母SPT4有助于进化上保守的着丝粒组蛋白H3变体(CenH3)Cse4p的正确定位。本实验室的主要研究目标是研究Cse4p及其相互作用伙伴(Scm3p和组蛋白H4)调节染色体忠实分离的分子机制。我们研究了Cse4p的定位机制，并证实了Cse4p的错误定位和组蛋白化学计量比的改变导致了染色体传递的缺陷。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会导致基因组的不稳定。我们研究了染色质修饰剂和动粒蛋白的翻译后修饰对CenH3染色质组装/功能的影响。我们的结果表明，着丝粒组蛋白H4的低乙酰化状态对于正确的染色体分离至关重要。我们最近关于Cse4p在酿酒酵母中的定位和组蛋白剂量的结果与在S.pombe中的结果一致，表明潜在的机制是保守的。我们还使用杂合二倍体菌株收集了大约6000株发芽酵母，进行了全基因组筛选，以定义单倍体不足于染色体稳定性的基因。这些分析的结果使我们能够确定在酵母和人类中维持基因组稳定的进化保守途径。我们对酿酒酵母中忠实染色体传递的分子决定因素的研究将有助于我们理解人类中类似的过程及其在人类疾病中的意义。我们的实验室独一无二地准备好利用传统的遗传、生化和细胞生物学方法，以及高通量基因组分析来进行我们的研究项目。我们使用一系列基因缺失菌株和菌落挑选机器人来识别可能的抗癌药物靶点，并通过合成基因组分析(SGA)进行基因筛查，该分析是由查理·布恩(多伦多大学)的实验室开发的。

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).