Loss of DUX causes minor defects in zygotic genome activation and is compatible with mouse development

How maternal factors in oocytes trigger zygotic genome activation (ZGA) is a long-standing question in developmental biology. Recent studies in 2-cell-like embryonic stem cells (2C-like cells) suggest that transcription factors of the DUX family are key regulators of ZGA in placental mammals^1,2. To characterize the role of DUX in ZGA, we generated Dux cluster knockout (KO) mouse lines. Unexpectedly, we found that both Dux zygotic KO (Z-KO) and maternal and zygotic KO (MZ-KO) embryos can survive to adulthood despite showing reduced developmental potential. Furthermore, transcriptome profiling of the MZ-KO embryos revealed that loss of DUX has minimal effects on ZGA and most DUX targets in 2C-like cells are normally activated in MZ-KO embryos. Thus, contrary to the key function of DUX in inducing 2C-like cells, our data indicate that DUX has only a minor role in ZGA and that loss of DUX is compatible with mouse development.