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Embryology is the discipline concerned with the study of embryogenesis, the development of the embryo from a fertilised egg cell. Findings in embryology have helped in the understanding of congenital abnormalities and developing assisted reproduction procedures.
The authors trace the emergence of porcine primordial germ cells and develop in vitro models of primordial germ cell development from human and monkey pluripotent stem cells in order to provide insight into early human development.
Didier Trono and colleagues show that both human DUX4 and mouse Dux are expressed before zygotic genome activation (ZGA) and lead to activation of ZGA-associated genes. Dux knockout in mouse embryonic stem cells prevents cycling through a 2-cell-like state, and zygotic depletion of Dux impairs embryonic development.
The endoderm layer destined to be primitive gut is a mosaic of earlier visceral endoderm and definitive endoderm that arises later, during gastrulation. Live imaging now reveals that in mouse embryos, definitive endoderm cells egress from underlying mesoderm and intercalate into the overlying cell layer. This process requires SOX17-mediated control of basement membrane organization.