Molecular Determinants of Chromosome Transmission and Cell Cycle Regulation

我们利用染色体传递保真度突变体和缺失菌株收集了S.酿酒酵母来识别和表征动粒功能和检查点功能所需的基因。对ctf突变体的研究导致了SPT 4和NUP 170在染色体分离和纺锤体组装检查点（SAC）功能中的作用的鉴定和表征。我们确定了Spt 4p在异染色质沉默中的新作用。使用跨物种的方法，我们表明，酵母spt 4菌株是由人SPT 4补充。最重要的是，我们证明了S。酿酒酵母SPT 4有助于进化上保守的着丝粒组蛋白H3变体（CenH 3）Cse 4p的正确定位。我们实验室的主要研究目标是研究调节Cse 4p及其相互作用伙伴（Scm 3 p和Histone H4）介导忠实染色体分离的分子机制。我们研究了Cse 4p定位的机制，并确定Cse 4p的错误定位和改变组蛋白化学计量导致染色体传递缺陷。我们的研究还表明，过表达Scm 3 p及其人类同源物HJURP导致酵母和人类系统中的基因组不稳定性。我们研究了染色质修饰剂和着丝粒蛋白的翻译后修饰对CenH 3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的低乙酰化状态是忠实的染色体分离的关键。我们最近的研究结果表明，Cse 4p在S. cerevisiae与S.粟酒裂殖酵母，这表明保护的基本机制。因此，S.酿酒酵母，阐明了Cse 4p定位的机制和染色质修饰在着丝粒功能中的作用，可能有助于我们了解人类和其他系统中的类似途径。 本研究对S.酿酒酵母将帮助我们了解人类的类似过程及其在人类疾病中的意义。我们的实验室是唯一准备利用传统的遗传，生物化学和细胞生物学方法，以及高通量基因组分析我们的研究项目。我们使用一系列基因缺失菌株和一个集落拾取机器人来识别可能的癌症药物靶点，并通过在Charlie Boone（多伦多大学）实验室开发的合成基因组分析（SGA）进行遗传筛选。

We have used chromosome transmission fidelity (ctf) mutants and the deletion strain collections of S. cerevisiae to identify and characterize genes required for kinetochore function and checkpoint function. Studies with the ctf mutants led to the identification and characterization of the roles of SPT4 and NUP170 in chromosome segregation and spindle assembly checkpoint (SAC) function. We established a novel role for Spt4p in heterochromatic silencing. Using a cross-species approach, we showed that the yeast spt4 strains are complemented by human SPT4. Most importantly, we showed 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. Thus, studies in S. cerevisiae that elucidate a mechanism for Cse4p localization and the role of chromatin modifications in centromere function may help us understand analogous pathways in humans and other systems. 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).