Project 2 - Role of dietary vitamin D supplementation levels in stability and function of the germline epigenome

PROJECT SUMMARY: Project 2 The germline carries genetic and epigenetic information essential to germ cell function and embryo development. Therefore, maintaining the integrity of the germline genome is a critical component of genetic lineage preservation. Genomic integrity of the genome is primarily determined by the stability of the genetic and epigenetic information it encodes and transmits to progeny. While most efforts to preserve mouse genetic lineages (and the phenotypes they carry) focus on preventing germline DNA sequence mutations, the occurrence and impact of germline epigenetic mutations (epimutations) are widely overlooked. This is especially concerning since it is well-established that environment (e.g., diet) can drive substantial changes to the germline epigenome that can perturb the phenotypes of subsequent progeny. Mouse diet is one of the most recognized environmental drivers of epigenetic changes but, surprisingly, is also one of the most variable environmental factors for laboratory mice with many different diets in use across different labs. The proposed study will build on our previous findings showing that depletion of the micronutrient vitamin D in mouse diet drives epimutations in the sperm genome. These studies will, for the first time, (i) Define the impact of variability in dietary vitamin D supplementation levels on germline epigenetic stability and the developmental potential of IVF-derived embryos; (ii) Identify candidate vitamin D-sensing genes that can serve as predictive markers of vitamin D-induced germline instability; and (iii) Support the development of diet recommendations for the MMRRC and its clients to enhance repository services and ensure optimal preservation of MMRRC strains and phenotypes they model. Overall, this work will generate new information about the impact of micronutrient supplementation in mouse chow diets on the stability of the germline epigenome that will inform recommendations for diet selection and reporting and quality control protocols for the MMRRC repositories and genetic lineage preservation efforts at large.