Identification of germline chromatin modifying factors that influence zygotic transcription activation in C. elegans

Precise control of the onset of transcription in post-fertilization embryos, often termed zygotic genome activation (ZGA), is essential to coordinate cell divisions and fate decisions to ensure proper development of the body plan. Maternally-contributed proteins and RNAs deposited in the zygote play an important role in ZGA, as does chromatin organization in pronuclei, yet the mechanisms by which parental germ cells anticipate the requirements for the first stages of ZGA is still not well understood. Using C. elegans as a model to study the epigenetic contributions from parental germ cells during the oocyte-to-embryo transition (OET), we previously demonstrated that histone modifications might act in germ cells to control ZGA. Here, we develop a novel assay to specifically track nascent transcription in gonads and embryos, which we use to identify chromatin regulatory factors acting in the germline that are responsible for subsequently promoting or inhibiting transcription during OET. This approach identifies regulation of both H3K4 methylation and H3K36 methylation in the parental germline as important contributors to successful ZGA and subsequent embryogenesis, and sets the stage for further mechanistic dissection of this critical developmental window upon the formation of a new organism.