DUX4 is a multifunctional factor priming human embryonic genome activation

Abstract

Double homeobox 4 (<i>DUX4</i>) is expressed at the early pre-implantation stage in human embryos. Here we show that induced human <i>DUX4</i> expression substantially alters the chromatin accessibility of non-coding DNA and activates thousands of newly identified transcribed enhancer-like regions, preferentially located within ERVL-MaLR repeat elements. CRISPR activation of transcribed enhancers by C-terminal DUX4 motifs results in the increased expression of target embryonic genome activation (EGA) genes <i>ZSCAN4</i> and <i>KHDC1P1</i>. We show that <i>DUX4</i> is markedly enriched in human zygotes, followed by intense nuclear DUX4 localization preceding and coinciding with minor EGA. <i>DUX4</i> knockdown in human zygotes led to changes in the EGA transcriptome but did not terminate the embryos. We also show that the DUX4 protein interacts with the Mediator complex via the C-terminal KIX binding motif. Our findings contribute to the understanding of <i>DUX4</i> as a regulator of the non-coding genome.