Grant: Project Grant

Recent studies reveal that many different genes that encode enzymes that turn on or off other genes by changing the structure of DNA are mutated in cancer as well as developmental disorders. These "regulatory" genes include Nsd1, Nsd2 and Setd2, each of which is mutated in patients with distinct developmental syndromes, as well as in specific cancers. Nsd1, Nsd2 and Setd2 encode enzymes that chemically modify a specific amino acid (#36) on a specific protein associated with DNA called histone H3. Patients with a related developmental syndrome have mutations in the gene Dnmt3a, which encodes an enzyme which chemically modifies the DNA itself- so called "DNA methylation". Interestingly, modifications of histone proteins are known to influence the activity of the enzymes that modify DNA. These observations suggest "cross-talk" between these enzymes, their substrates and in turn the genes they regulate. DNA methylation is known to play a particularly important role in germline development- the process of forming the sperm and the egg. We showed recently that Setd2 is required for DNA methylation in the egg. However, we also found that this gene is entirely dispensable for DNA methylation in male germ cells, raising the question, does modification of H3 play a role in DNA methylation in the cells that give rise to the sperm? Here, using the mouse as a model system and genetic engineering, we propose to study the consequences of removing NSD1 or NSD2 on DNA methylation in male germ cells. This "genome-wide" study, applying state-of-the-art DNA sequencing technology, will lead to a better understanding of the role of histone marks and the enzymes that deposit them in directing DNA methylation in normal germ cell developmental, potentially leading to new avenues for treatment of developmental disorders and cancer in which the genes that encode these enzymes are mutated.