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Free keywords:
X chromosome
Gene dosage
Embryonic stem cells
Sex differences
Pluripotency
MAPK signaling
CRISPR screen
Dusp9
Klhl13
Abstract:
X-chromosomal genes contribute to sex differences, in particular during early development, whenboth X chromosomes are active in females. Here, double X-dosage shifts female pluripotent cells towards the naive stem cell state by increasing pluripotency factor expression, inhibiting thedifferentiation-promoting MAP kinase (MAPK) signalling pathway and delaying differentiation. Toidentify the genetic basis of these sex differences, we have performed a series of CRISPR knockoutscreens in murine embryonic stem cells to comprehensively identify X-linked genes that cause thefemale pluripotency phenotype. We found multiple genes that act in concert, among which Klhl13plays a central role. We show that this E3 ubiquitin ligase substrate adaptor protein promotes pluripotency factor expression, delays differentiation and represses MAPK target genes, and weidentify putative substrates. We thus elucidate the mechanisms that drive sex-induced differences inpluripotent cells with implications for gender medicine in the context of induced pluripotent stem cellbased therapies.