Mechanism of Dmc1-mediated Meiotic Recombination in Budding Yeast

同源重组在减少染色体分离中起着关键作用 减数分裂。减数分裂重组是由 DNA 双链的程序诱导启动的 DSB 断裂，涉及有丝分裂中 DSB 重组修复相关的机制 细胞。减数分裂重组受到独特的调控过程的影响，促进 同源染色单体之间而不是姐妹染色单体之间的重组，并且还调节 交叉型重组事件的频率，以确保所有同源染色体 两人至少参加一项此类活动。重组的核心步骤是同源 链入侵和交换。出芽酵母和包括人类在内的许多其他生物体 有一种专门的减数分裂重组酶 Dmc1，它催化减数分裂的核心步骤 重组涉及 DNA 序列同源性搜索，最终形成 DNA 链交换形成连接重组伙伴的杂交 DNA 区域。一个不同的 链交换蛋白 Rad51 催化有丝分裂重组的核心步骤。 Dmc1 有 一组独特的减数分裂特异性辅助蛋白，但也受到有丝分裂的调节 重组蛋白，包括有丝分裂重组酶 Rad51。 Rad51 是从 在减数分裂过程中，有丝分裂中的酶转化为 Dmc1 辅助蛋白。我们小组研究的是 Dmc1促进减数分裂重组的分子机制。我们力求 了解 Dmc1 的活性如何受到其每种辅助蛋白的调节。这个目标是 通过结合广泛的先进实验方法来实现。特别是 重要的是我们小组在生化重建重组过程方面的独特努力 使用纯化的成分。为了补充我们的生化研究，我们首先开发了 研究减数分裂的结构和动力学所需的工具和方法 使用超分辨率光学显微镜重组体。我们组还采用分子 允许检测断裂和分支 DNA 重组的遗传技术 中间体，以及重组过程中发生的蛋白质-蛋白质相互作用 过程。我们寻求结合这些方法来揭示重要的机制特征 重组过程，包括控制它的调节机制。

Homologous recombination plays a critical role in reductional segregation of chromosomes in meiosis. Meiotic recombination is initiated by the programmed induction of DNA double strand breaks (DSBs) and involves a mechanism related to recombinational repair of DSBs in mitotic cells. Meiotic recombination is subject to unique regulatory processes that promote recombination between homologous chromatids rather than sister chromatids and also regulate the frequency of crossover type recombination events to ensure all homologous chromosome pairs engage in at least one such event. The central step of recombination is homologous strand invasion and exchange. Budding yeast and many other organisms including humans have a specialized meiotic recombinase, Dmc1, that catalyzes the central step of meiotic recombination which involves DNA sequence homology searching that culminates in DNA strand exchange to form regions of hybrid DNA that connect recombining partners. A different strand exchange protein, Rad51, catalyzes the central step of mitotic recombination. Dmc1 has a unique set of meiosis-specific accessory proteins, but is also regulated by mitotic recombination proteins, including the mitotic recombinase Rad51. Rad51 is converted from an enzyme in mitosis into to a Dmc1 accessory protein during meiosis. Our group studies the molecular mechanism through which Dmc1 promotes meiotic recombination. We seek to understand how Dmc1’s activity is regulated by each of its accessory proteins. This goal is achieved by combining a wide range of advanced experimental approaches. Of particular importance is our group’s unique effort to biochemically reconstitute the recombination process using purified components. To complement our biochemical studies, we were first to develop the tools and methods required to study the architecture and dynamics of meiotic recombinosomes using super-resolution light microscopy. Our group also employs molecular genetic techniques that allow detection of broken and branched DNA recombination intermediates, as well as the protein-protein interactions that occur during the recombination process. We seek to combine these approaches to uncover important mechanistic features of the recombination process including the regulatory mechanisms that control it.