Matthew Hurton, Lee Lab
Characterizing the embryonic gene regulatory landscape in zebrafish
Early embryos undergo dramatic gene regulatory changes. Initially, the zygotic genome is transcriptionally silent, and maternally provided RNAs drive embryogenesis. Subsequently, embryonic transcription begins, and the large influx of embryonic transcripts results in a switch from maternal to zygotic control of embryogenesis. In zebrafish, three maternal transcription factors, Nanog, Sox19b, and Pou5f3, activate the majority, but not all, of embryonic genes. Other maternally provided factors, therefore, likely drive the remainder of embryonic transcription by engaging embryonic regulatory sequences. In this talk, I will present our on-going efforts to identify and characterize this regulation. By mapping embryonic regulatory sequences (enhancers) genome wide, I aim to identify candidate maternal regulators of embryonic gene activation. I have adapted CUT&RUN, a novel low-input alternative to ChIP-Seq, for use in zebrafish to identify these early enhancers. Using CUT&RUN directed against the activating histone modification H3K27ac, I have identified putative enhancers and found the DNA-binding motifs for several candidate maternal activators. Based on these results, I have begun generating several conditional loss of function fish lines to evaluate these factors’ roles in regulating genome activation. Together, these analyses will expand our understanding of genetic regulation in the early embryo and how transcriptional reprogramming effects fundamental changes to cellular identity.
May 8, 2020
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12PM