DUX-miR-344-ZMYM2-mediated activation of MERVL LTRs induces a totipotent 2C-like state [RNA-seq]

Mouse embryonic stem cells (ESCs) sporadically express preimplantation two-cell-stage (2C) transcripts, including MERVL endogenous retrovirus and Zscan4 cluster genes. Such 2C-like cells (2CLCs) can contribute to both embryonic and extraembryonic tissues when reintroduced into early embryos. We examined global nucleosome occupancy and gene expression in 2CLCs and identified miR-344 as the noncoding molecule that positively controls 2CLC potency. We found that activation of endogenous MERVL or miR-344-2 alone is sufficient to induce 2CLCs with induction of 2C genes and an expanded potency. Mechanistically, miR-344 is activated by the 2C-state driver DUX and post-transcriptionally represses ZMYM2 and LSD1, which recruit the HDAC corepressor to MERVL LTR for transcriptional repression. Consistently, zygotic depletion of Zmym2 compromises the totipotency-to-pluripotency transition during early development. Our studies establish the novel DUX->miR-344--|Zmym2/Lsd1 axis that controls MERVL for expanded stem cell potency. Overall design: RNA sequencing analysis was performed in WT, Zmym2KO, miR344-activated, and MERVL-activated ESCs, and embryos with miR-344 mimics or siZmym2 injection.