The Mechanism and Function of SDG2 in Regulating Chromatin Structure and Gene Expression

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

Intellectual Merit: In eukaryotic cells, DNA is packaged into chromatin by wrapping around histone octamers. Many molecular processes that take place at the chromatin level are profoundly affected by the structural properties of the chromatin. A large body of work in recent years has established the importance of post-translational modifications of histones, such as methylation of lysine residues, in modulating chromatin structure and gene expression. The SDG2 protein in Arabidopsis thaliana is a member of a previously uncharacterized and highly conserved lineage of putative lysine methyltransferases. Loss-of-function sdg2 mutant plants exhibit numerous developmental abnormalities and the mis-regulation of hundreds of genes, as well as histone methylation defects at specific loci. These results indicate that SDG2 is critically important in regulating gene expression and plant development. This project is directed to elucidate the mechanism of action and function of SDG2. The first aim is to understand the function of SDG2 by genome-wide identification of the genes that are directly regulated by SDG2 and the histone methylation defects caused by the loss of SDG2. The second aim is to understand the mechanism by which SDG2 modifies histones by determining its enzymatic and substrate specificities. The third aim is to understand how SDG2 is targeted to specific genes during development by isolating proteins that interact with SDG2. These studies are expected to reveal significant insights into the mechanisms and functions of SDG2. In addition, considering the complex and intimate interactions among different histone modification pathways, the results from this project are also expected to assist in the broader understanding of the mechanisms and functions of histone modifications. Broader Impacts: The broader impacts of this project are several fold. The research is multi-disciplinary in nature and therefore ideally suited for training future scientists, including undergraduate research assistants, a graduate student and a postdoctoral research associate. This project will also have an immediate and positive impact on teaching. The PI teaches a lecture series on plant genetics and molecular biology, with emphasis on the use of genomic approaches to study complex biological processes. This course should benefit tremendously from the ideas conceived and the knowledge gained from this project. In addition, the PI will be actively engaged in two programs designed to promote K-12 science education by enhancing the classroom and hands-on training of current and future middle school science teachers. The PI will develop an undergraduate course for future middle school science teachers (current education major students) with a particular emphasis on injecting enthusiasms into and stimulating the curiosities of science teachers, which will be relayed to middle school students in the future. Also, the PI will participate in the Georgia Intern-Fellowships for Teachers (GIFT) by sponsoring current teachers for summer research. This program is expected to improve the critical thinking and problem solving abilities of the teachers, and to help them connect real-world scientific research and application with the "textbook science" that they teach in the classroom.