Developmental functions of insect Dbf4 link replication and transcription

Dbf 4连接复制和转录的昆虫发育功能细胞每次分裂时都会复制它们的DNA，这一过程受到真菌、昆虫和其他动物中发现的专门蛋白质的精心控制。在昆虫中，这些DNA复制的关键调节因子之一已经进化出化学修饰染色体蛋白质的第二个重要作用。该项目旨在了解这两种功能如何以及为什么在单个基因中结合，因为这可以提供一种机制来协调DNA复制与其他染色体过程。从长远来看，这项研究可以确定杀虫剂的新靶标，也可以提高我们对不同生物体中DNA复制和基因表达如何控制和协调的理解。研究生将作为该项目的一部分接受培训，该项目还提供基于本科课程的研究经验（CURE）。该CURE旨在让本科生在大学生涯中尽早参与真实的研究经验，以提高他们的学习成绩，保留科学，技术，工程和数学（STEM），并提高他们的实验室研究技能。DNA复制是由两种激酶CDK和Cdc 7的作用启动的，这两种激酶都需要结合调节亚基才能活动。Dbf 4是Cdc 7的调节亚基，这些亚基中的任何一个的缺失都会破坏从酵母到哺乳动物的生物体中的DNA复制和有丝分裂。以前的研究表明，雪纺，在果蝇中的单一可识别的Dbf 4同源物，结合并激活果蝇Cdc 7（dCdc 7）。与DNA复制和活力所必需的dCdc 7相反，Chiffon的dCdc 7结合活性不是发育所必需的。相反，雪纺有第二个复制独立的功能，这是必不可少的;它结合Gcn 5和成核形成的昆虫特异性组蛋白乙酰转移酶复合物，雪纺组蛋白乙酰转移酶（CHAT）。令人惊讶的是，CHAT可以取代良好表征Gcn 5转录辅激活因子Spt-Ada-Gcn 5乙酰转移酶（佐贺）在发展过程中。由于佐贺的组蛋白乙酰转移酶活性刺激转录，因此本项目的假设是，CHAT引起的组蛋白乙酰化对于果蝇生长和发育所必需的基因的适当转录激活是必要的。该项目将确定需要CHAT进行适当基因表达的基因，表征CHAT的全基因组分布，并探索控制DDK与CHAT复合物的细胞类型特异性表达的机制。总的来说，这些研究将提供深入了解基因组复制，染色质修饰和转录的动态和时空协调。该奖项反映了NSF的法定使命，并已被认为是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的支持。

Developmental functions of insect Dbf4 link replication and transcriptionCells copy their DNA each time they divide in a process that is carefully controlled by specialized proteins that are found in fungi, insects, and other animals. In insects, one of these key regulators of DNA replication has evolved a second essential role to chemically modify chromosomal proteins. This project seeks to understand how and why these two functions are combined within a single gene, since this could provide a mechanism to coordinate DNA replication with other chromosomal processes. In the long term, this research could identify novel targets for insecticides, and could also enhance our understanding of how DNA replication and gene expression are controlled and coordinated in different organisms. Graduate students will be trained as part of this project, which also provides an undergraduate course-based research experience (CURE). This CURE aims to involve undergraduate students in authentic research experiences as early as possible during their university career to enhance their academic performance, retention in Science, Technology, Engineering and Math (STEM), and improve their laboratory research skills.DNA replication is initiated by the action of two kinases, CDK and Cdc7, which both require binding of regulatory subunits for activity. Dbf4 is the regulatory subunit for Cdc7, and loss of either of these subunits disrupts DNA replication and mitosis in organisms from yeast to mammals. Previous studies showed that Chiffon, the single identifiable Dbf4 homolog in Drosophila, binds and activates Drosophila Cdc7 (dCdc7). In contrast to dCdc7, which is essential for DNA replication and viability, the dCdc7-binding activity of Chiffon is not required for development. Instead, Chiffon has a second replication-independent function that is essential; it binds Gcn5 and nucleates formation of an insect-specific histone acetyltransferase complex, Chiffon Histone Acetyltransferase (CHAT). Surprisingly, CHAT can substitute for the well characterized Gcn5 transcriptional coactivator Spt-Ada-Gcn5 acetyltransferase (SAGA) during development. Since the histone acetyltransferase activity of SAGA stimulates transcription, the hypothesis of this project is that histone acetylation by CHAT is necessary for proper transcription activation of genes that are essential for Drosophila growth and development. This project will identify genes that require CHAT for proper gene expression, characterize the genome-wide distribution of CHAT, and explore the mechanisms that control cell type-specific expression of the DDK versus CHAT complexes. Overall, these studies will provide insight into the dynamics and spatiotemporal coordination of genome replication, chromatin modification and transcription.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.