Meeting Abstract
128.8 Tuesday, Jan. 7 15:15 Epigenetic regulation of alternative developmental trajectories in an annual killifish ROMNEY, A L*; PODRABSKY, J E; Portland State University; Portland State University arom2@pdx.edu
The annual killifish, Austrofundulus limnaeus, is capable of entering into a state of metabolic and developmental dormancy during embryogenesis termed diapause. However, individuals may also follow an alternative phenotypic trajectory and instead “escape” entry into diapause and develop continuously until hatching. Early development along the two trajectories is indistinguishable, and gene regulatory mechanisms are currently unknown. Phenotype appears to be influenced by maternal provisioning based on the observation that young females produce predominately escape embryos and older females produce diapausing embryos. In addition, the incubation temperature of embryos can alter trajectory. Maternal provisioning is known in many vertebrates to direct early development prior to the initiation of embryonic gene transcription. I hypothesize that maternally packaged gene products coordinate the cellular events that determine developmental trajectory in A. limnaeus. In addition, I propose the expression of specific environmentally-responsive microRNAs during development that can override maternal provisioning. Using RNA-seq, we have generated complimentary transcriptomic profiles of messenger RNAs (mRNAs) and microRNAs during embryogenesis of A. limnaeus. Embryos that are destined for either the diapause or escape phenotypes have unique expression patterns starting at fertilization; well before they are morphologically distinct. Our findings suggest maternal programming of diapause through the packaging of specific mRNAs as well as temperature induced microRNAs that target maternal transcripts to alter developmental trajectory. These results will not only impact our understanding of genetic mechanisms that regulate entrance into diapause, but will also provide insight epigenetics and development.
