Intellectual Merit: Different types of cells rely on the expression of distinct sets of genes for their development and function. Altering the accessibility of different sets of genes is one way genes can be regulated. The accessibility of genes can rely on incorporating histone H2A variants into the nucleosomes that compact DNA. For example, C. elegans express H2A variants that include the evolutionarily conserved H2A.Z (HTZ-1) and the sperm-specific HTAS-1. This project will test the hypothesis that structural differences in HTZ-1 and HTAS-1 alter DNA accessibility to regulate gene expression in a cell-type specific manner. First, biophysical approaches will define structural properties of C. elegans H2A proteins. Second, fluorescence resonance energy transfer (FRET) and biochemical approaches will identify differences in the stability, DNA unwrapping, and packing of nucleosomes containing H2A, HTZ-1, and HTAS-1. Cytological assays conducted in genetic mutants will correlate how H2A variant incorporation affects gene expression. Swapping domains of HTZ-1 and HTAS-1 with H2A in vitro and in vivo will identify structural domains of these H2A variants that are important for their incorporation and roles in transcription in distinct cell types. Overall, these studies will elucidate the structural properties of C. elegans histone H2A variants that contribute to the specification of different cell types.
Broader Impacts: The research will be conducted at San Francisco State University, a historically minority-serving public institution. Undergraduate and master's students from the Biology and Chemistry and Biochemistry programs will be trained by the PI and her collaborators at SFSU and UCSF in the theory and practice of biochemical, biophysical, and molecular genetic methodology to understand fundamental aspects of DNA organization and transcriptional regulation. Students will work in cohorts to share resources, ideas, and expertise. Under the supervision of the PI, students will learn to critically evaluate scientific research, plan experiments, and interpret experimental data to become independent critical thinkers. The interdisciplinary training and mentorship provided by the proposed work will provide a strong foundation to advance the education and careers of SFSU's diverse students in the sciences.
