CENP-N特异性识别CENP-A核小体的分子机制研究

The transmission of intact genome to daughter cells during cell division is a fundamental requirement for the viability of orgamisms. To achieve faithful segregation of sister chromatids, chromosomes rely on a specialized region known as the centromere. During mitosis, The centromere directs assembly of kinetochore, which is a proteinaceous macromolecular structure that forms attachments to spindle microtubules. Defects in centromere or kinetochore function can lead to genomic instability, resulting in developmental defects or disease. In most eukaryotes, the site of centromere formation and maintenance is not depend on specific DNA sequences, but epigenetically determined by the presence of specialized nucleosomes containing the histone H3 variant centromere protein A ( CENP-A; also known as CENH3 ). The CENP-A nucleosome is sufficient to specify the site of functional centromere formation by recruit a 16-subunit Constitutive Centromere-Associated Network ( CCAN ), which is localizes to centromeres throughout the cell cycle and provides the foundation for outer kinetochore assembly on centromere. Among the 16 subunit of CCAN, only CENP-C and CENP-N bind to CENP-A nucleosomes directly. Previous work has revealed the molecular mechanism for CENP-A nucleosome recognition by CENP-C. But the recognition mechanism for CENP-N specifically bind to CENP-A nucleosome is still elusive. In this project, we aim to resolve the crystal structure of CENP-N/CENP-A nucleosome complex, reveal the molecular mechanism of CENP-A nucleosome recognition by CENP-N. These results will provide important insights into our understanding of the epigenetic inheritance of centromere, and help us to find new clues to prevent and treat diseases caused by genomic instability.

细胞在有丝分裂时,要达成染色体的精确分离，需要依赖染色体上的着丝粒区域。着丝粒通过指导动粒的组装，形成与纺锤体微管的连接。着丝粒或动粒的功能缺失可能导致基因组不稳定性，进而诱导多种疾病的发生。在绝大多数真核生物中，着丝粒的位置是由包含CENP-A（组蛋白H3的变体）的核小体通过表观遗传方式决定的。CENP-A核小体招募CCAN蛋白复合物到着丝粒上，形成动粒组装的基础。在CCAN复合物16种蛋白亚基中，只有CENP-C和CENP-N能直接结合CENP-A核小体。但CENP-N特异性结合CENP-A核小体的分子机制仍不得而知。在本项目中，我们将通过解析CENP-N和CENP-A核小体复合物的晶体结构，阐明CENP-N特异性识别CENP-A核小体的分子基础。为我们深入理解着丝粒的表观遗传特性提供重要信息。为预防和治疗基因组不稳定性导致的发育缺陷和癌症等疾病提供新的思路。

细胞在有丝分裂时,要达成染色体的精确分离，需要依赖染色体上的着丝粒区域。着丝粒通过指导动粒的组装，形成与纺锤体微管的连接。着丝粒或动粒的功能缺失可能导致基因组不稳定性，进而诱导多种疾病的发生。在绝大多数真核生物中，着丝粒的位置是由包含CENP-A（组蛋白H3的变体）的核小体通过表观遗传方式决定的。CENP-A核小体招募CCAN蛋白复合物到着丝粒上，形成动粒组装的基础。在CCAN复合物16种蛋白亚基中，只有CENP-C和CENP-N能直接结合CENP-A核小体。但CENP-N特异性结合CENP-A核小体的分子机制仍不得而知。在本项研究中，我们将通过解析CENP-N和CENP-A核小体复合物的结构，阐明CENP-N特异性识别CENP-A核小体的分子基础。为我们深入理解着丝粒的表观遗传特性提供重要信息。为预防和治疗基因组不稳定性导致的发育缺陷和癌症等疾病提供新的思路。经过3年的研究，我们未能解析CENP-N和CENP-A核小体复合物的结构。