Duxbl-mediated suppression of ZGA drives totipotency to pluripotency transition in mice II

In mammalian embryos, Dux transcription factors (TF) drive a cleavage stage-specific transcriptional burst associated with zygotic genome activation (ZGA) during which hundreds of genes and endogenous retroviral (ERV) elements are transiently expressed. In mice, ZGA begins in late 1-cell (1C) embryos and is shut down within hours at the late 2-cell (2C) to 4-cell (4C) stage. While this transition is accompanied by the loss of totipotency, it is not clear whether shutdown of Dux-induced ZGA is required for this process and how ZGA is terminated. Here, we reveal an essential negative feedback axis by which the Dux family member Duxbl terminates Dux-induced ZGA from the mid 2C stage onward by direct suppression of genomic Dux target loci. Consequently, Duxbl inactivation results in sustained expression of Dux-induced ZGA leading to 4C arrest. Our study reveals the Dux/Duxbl axis that determines the timing of totipotency exit enabling the very first divergence of cell fates. Overall design: ES-E14TG2a cells were transfected with a control plasmid or plasmid encoding Dux or Duxbl. 16 h after plasmid transfection, gene expression was induced by addition of Doxycyline to a final concentration of 100 ng/ml for 18 h. Next, RNA was isolated for RNA-seq.