Scientists have discovered a process during mammalian embryonic development that is critical for early embryos to develop into healthy blastocysts.

Transformation from morula to blastocyst is a defining event of preimplantation embryo development. During this transition, the embryo must establish a paracellular permeability barrier to enable expansion of the blastocyst cavity.

Using advanced microscopy techniques and live mouse embryos, the researchers observed rings of actin – a main component of a cell’s cytoskeleton – forming on the surface of the embryo.

The study, jointly led by Dr Maté Biro of UNSW Medicine and Dr Nicolas Plachta of the Agency for Science, Technology and Research (A*STAR) in Singapore, is published in the journal Cell.