Study of how species-specific interactions with the proliferating cell nuclear antigen of Trypanosoma brucei impact DNA replication

增殖细胞核抗原（PCNA）是所有真核生物中保守的。关于PCNA相互作用以及它们如何调节真核生物中DNA复制的知识主要来自酵母和动物细胞中的研究。本项目将研究PCNA在不同真核生物谱系中的相互作用，单细胞寄生虫布氏锥虫，代表原生生物，最多样化的真核生物群。T.布氏杆菌有一个独特的附加结构元件，一个大的背侧环，被称为TbERK 8的促分裂原活化蛋白激酶磷酸化。这种相互作用不发生在酵母或动物细胞的PCNA同源物中。这项研究的重要性在于它对增加PCNA调节真核生物DNA复制的机制的进化和多样性的基础知识的影响。该项目将为来自代表性不足的群体和历史上黑人大学和学院（HBCU）的本科生和研究生提供体验式培训，以帮助培养下一代多样化的基础研究人员。许多研究表明，PCNA通过与其他蛋白质相互作用的方式作为DNA复制的主调节器发挥作用。到目前为止，大多数研究PCNA的功能，使用标准的模型，如酵母和动物细胞，属于同一谱系的真核生物。此外，迄今为止研究的所有PCNA相互作用都发生在其正面。本项目将通过两种策略来揭示真核生物DNA复制的新知识：首先，它将使用T。布氏锥虫是代表真核生物中最多样化类群的原生生物;锥虫是在酵母或后生动物之前从真核生物祖先谱系中分裂出来的，它们的DNA复制机制和调控机制知之甚少。其次，本项目将重点关注TbPCNA的大背侧环，其在丝氨酸和苏氨酸残基上磷酸化并与其他背侧环相关蛋白（BSL-AP）相关。本项目通过研究T.布鲁塞。研究两个未表征的锥虫特异性BSL-AP如何与TbPCNA背面环相互作用，将推进真核DNA复制中涉及的新基因功能的知识。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Proliferating cell nuclear antigen (PCNA) is conserved in all eukaryotes. The knowledge about PCNA interactions and how they regulate DNA replication in eukaryotes comes mostly from the studies in yeast and animal cells. This project will study PCNA interactions in a different lineage of eukaryotes, the single-cell parasite Trypanosoma brucei, representing protists, the most diverse group of eukaryotes. The PCNA of T. brucei has a unique added structure element, a large backside loop that is phosphorylated by a mitogen-activated protein kinase called TbERK8. Such an interaction does not occur in the PCNA homologs from yeast or animal cells. The importance of this study is in its impact on increasing fundamental knowledge of the evolution and diversity of mechanisms used by PCNA to regulate DNA replication in eukaryotes. This project will provide experiential training to undergraduate and graduate students from underrepresented groups and Historically Black Universities and Colleges (HBCUs) to help train the next generation of diverse basic researchers.Many studies show that PCNA functions as a master regulator of DNA replication by way of interactions with other proteins. Thus far, PCNA functions were mostly investigated using standard models such as yeast and animal cells, which belong to the same lineage of eukaryotes. Moreover, all the PCNA interactions studied to date occur on its front face. This project will uncover new knowledge about eukaryotic DNA replication using two strategies: Firstly, it will use T. brucei, a protist representing the most diverse group of eukaryotes; trypanosomatids split from the eukaryotic ancestor lineage before yeast or metazoa, and their DNA replication machinery and mechanisms of regulation are poorly understood. Secondly, this project will focus on the large backside loop of TbPCNA that gets phosphorylated on serine and threonine residues and associates with other backside loop-associated proteins (BSL-APs). This project has the potential to advance knowledge of eukaryotic DNA replication by studying how the phosphorylation status of the backside loop and its interaction with BSL-APs regulate DNA replication in T. brucei. Examining how two uncharacterized trypanosome-specific BSL-APs interact with the TbPCNA backside loop will advance knowledge of novel gene functions involved in eukaryotic DNA replication.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.