Khdc3 Regulates Metabolism Across Generations in a DNA-Independent Manner [II]

Genetic variants can alter the profile of heritable molecules such as small RNAs in sperm and oocytes, and in this manner ancestral genetic variants can have a significant effect on offspring phenotypes even if they are not themselves inherited. Here we show that wild type female mice descended from ancestors with a mutation in the mammalian germ cell gene Khdc3 have hepatic metabolic defects that persist over multiple generations. We find that genetically wild type females descended from Khdc3 mutants have transcriptional dysregulation of critical hepatic metabolic genes, which persist over multiple generations and pass through both female and male lineages. This was associated with dysregulation of hepatically-metabolized molecules in the blood of these wild type mice with mutational ancestry. The oocytes of Khdc3­-null females, as well as their wild type descendants, had dysregulation of multiple small RNAs, suggesting that these epigenetic changes in the gametes transmit the phenotype between generations. Our results demonstrate that ancestral mutation in Khdc3 can produce transgenerational inherited phenotypes, potentially indefinitely. Overall design: Serum from wild type females descended from wild type ancestors (WT) or wild type females descended from Khdc3-null ancestors (WT*) was injected intraperitoneally into genetically wild type females (n=2). IP injections consisted of 200µl pooled serum that were injected every 12 hours for 3 doses (each mouse received a total of 600µl injected serum). The female WT mice were subsequently mated with a WT male 24 hours later. Livers from female mice of each offspring were dissected at 1 month of life. RNA was extracted and RNA sequencing was performed on the samples (n=4).