减数分裂是真核生物有性生殖产生单倍体配子的必需环节，其核心事件包括同源染色体间的配对、联会、重组和分离。染色体的构建，包括相对松散的常染色质和高度浓缩的异染色质，对减数分裂核心事件的顺利进行至关重要。迄今，减数分裂过程中特异的异染色质形成和浓缩机制尚不清楚。本项目前期研究发现DNA聚合酶POLε参与减数分裂异染色质的形成，并证明其催化亚基的N端和C端分别识别染色质浓缩因子MORC1和组蛋白H3.1。在此基础上，本研究将深入研究：1）POLε与其互作因子的染色质浓缩表型及遗传关系；2）POLε如何识别并招募MORC1；3）POLε的C端锌指结构域结合组蛋白H3.1的分子基础和体内功能；4）POLε调控减数分裂基因沉默的功能。本研究最终将阐明DNA聚合酶POLε在执行DNA复制功能后，如何通过其C端装载组蛋白H3.1，并通过N端招募浓缩因子MORCs，进而形成高度浓缩的异染色质的分子机制。

Meiosis is essential for generating haploid games during sexual reproduction in most eukaryotes and its crucial events include paring, synapsis, recombination and segregation between homologous chromosomes. Chromosomes are composed of relatively less condensed euchromatin and extremely condensed heterochromatin, which ensure the normal progression of homolog chromosomes interaction. To date, the molecular mechanisms in regulating meiotic heterochromatin condensation remain largely unknown. We previously found that Arabidopsis catalyze subunit of DNA polymerase POL ε (POLE1) is required for the normal formation of meiotic heterochromatin, and demonstrated that POLE1-N and -C termini specifically interact with chromosome condensation factor ATPase MORC1 (microrchidia 1) and histone variant H3.1，respectively. Based on the previous results, this project will in depth study: 1) the phenotypes and genetic relationship between the mutants of POLE1 and MORC1; 2) the regulatory mechanism of recruitment of MORC1 by POL ε; 3) the molecular basis and in vivo function of selectively recognition of histone variant H3.1 by the C-terminal zinc finger domain of POL ε; 4) the role of POL ε in gene silencing during meiosis. Taken together, this project will finally address the molecular mechanisms of which POL ε specifically recognizes histone variant H3.1 by its C-terminal zinc finger domain and recruits chromosome condensation factor MORC1 by its N-terminal EXO domain, thus ensuring meiotic heterochromatin condensation.