Centromere Assembly

在有丝分裂和减数分裂中确保染色体准确分离的过程对细胞的存活和稳定至关重要。着丝粒是一种基本的染色体结构，具有多种功能，是将复制的染色体忠实地分离到子代细胞所必需的。该项目将对导致着丝粒形成和维持的分子机制提供新的见解。此外，该项目将为圣安东尼奥地区的博士后、研究生、本科生和高中生提供研究和培训机会，他们中的许多人是代表不足的少数民族和弱势群体。该项目的目标是确定导致着丝粒形成和维持的因素和步骤。CENP-A蛋白的泛素化对CENP-A着丝粒的沉积和组装是必不可少的；因此，假设识别依赖泛素的CENP-A相互作用将为控制着丝粒组装和维持的机制提供关键信息。以下特定目标验证了这一假说：(1)确定Rad50(和MRN复合体)在CENP-A在着丝粒沉积中的作用及其在着丝粒核小体中的稳定性(初步数据表明这些蛋白质在依赖泛素化的与CENP-A的相互作用中)；以及(2)确定R-环在CENP-A在着丝粒沉积中的作用(初步数据表明参与R环形成和分解的RNA解旋酶A参与与CENP-A的泛素化依赖的相互作用)。这项工作的知识意义在于新的机械信息，这对理解染色体分离的保真度至关重要。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The processes that ensure accurate chromosome segregation in mitosis and meiosis are critical for cellular viability and stability. The centromere is an essential chromosomal structure with multiple functional roles necessary for faithful segregation of replicated chromosomes to daughter cells. This project will provide new insights into molecular mechanisms that lead to formation and maintenance of centromeres. In addition, the project will provide research and training opportunities to postdoctoral, graduate, undergraduate and high school students in the San Antonio area, many of whom are under-represented minorities and underprivileged.The goal of the project is to determine the factors and steps responsible for centromere formation and maintenance. Ubiquitylation of CENP-A protein is essential for CENP-A centromere deposition and assembly; hence, the hypothesis is that identification of ubiquitin-dependent CENP-A interactors will provide crucial information about mechanisms that control centromere assembly and maintenance. The following specific aims test this hypothesis: (1) determine the role of RAD50 (and the MRN complex) in CENP-A deposition at the centromere and its stability in centromeric nucleosomes (preliminary data implicate these proteins in ubiquitylation-dependent interactions with CENP-A); and (2) determine the role of R-loops in CENP-A deposition at the centromere (preliminary data implicate RNA helicase A, which is involved in R-loop formation and resolution, in ubiquitylation-dependent interactions with CENP-A). The intellectual significance of this work lies in novel mechanistic information that is vital to understanding the fidelity of chromosome segregation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.