Oogenesis

The maternal diet can impact offspring development, yet the mechanisms responsible for this remain largely unknown. New research shows that oocyte metabolites, specifically NAD⁺ and the methyl donor S-adenosylmethionine, can mediate the impact of maternal nutrient stress on the progeny through metabolic reprogramming in Drosophila.

Mice deficient in the piRNA pathway display sterility only in males. Taking advantage of a more representative piRNA pathway in golden hamsters, three studies now demonstrate that the piRNA pathway is essential for fertility in hamsters of both sexes and thus strongly link this small RNA pathway to fertility regulation in both men and women.

Assembling egg cells involves cytoplasmic and nuclear processes that together enable embryonic development. A study now defines a set of transcription factors required for cytoplasmic, but not key nuclear, processes.

Maternal high-fat diet has a negative impact on fertility—including an apparent direct effect on early development. In this issue, a new study connects this phenotype to depletion of Stella protein in oocytes, demonstrating environmental regulation of a maternal-effect gene.

How maternal diet influences offspring metabolism is unclear, as it is difficult to distinguish between the effects of the in utero environment and epigenetic factors contributed by the oocyte. In a mouse model of high-fat diet, a new study teases apart these mechanisms by using in vitro fertilization and shows that susceptibility of offspring to metabolic disorder can likely be attributed to epigenetic inheritance via the oocyte.