Gene expression regulating blastocyst formation

Regulation of blastocyst formation

“…Compaction represents the onset of cellular differentiation during mammalian development as the outer cells of the conceptus begin to polarize as a prelude to trophectoderm differentiation (7,17,18). Blastocyst formation is the morphogenetic event that follows compaction in this continuum of preimplantation development (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Each succeeding phase of this developmental interval is dependent upon preceding events.…”

“…This interval called preimplantation or pre-attachment development (depending upon the species) is uniquely mammalian and encompasses the free-living period of mammalian development during which the early conceptus traverses the oviduct and gains access to the uterine environment (1)(2)(3)(4)(5)(6). This period culminates in the formation of an embryonic structure called the blastocyst, which is composed of the outer epithelial trophectoderm, a fluid-filled cavity and small group of cells called the inner cell mass, which are the progenitors of the embryo proper (6)(7)(8)(9)(10)(11)(12). The blastocyst is not simply the vessel that delivers its cargo of inner cell mass cells to the uterus as it contains the specialized cell type (the trophectoderm), which will mediate the maternalfetal interactions required to support eutherian embryogenesis.…”

“…The blastocyst is not simply the vessel that delivers its cargo of inner cell mass cells to the uterus as it contains the specialized cell type (the trophectoderm), which will mediate the maternalfetal interactions required to support eutherian embryogenesis. The trophectoderm cells differentiate into the trophoblast to mediate either invasion or attachment to the uterus during implantation and as a prelude to their subsequent contribution to placental structures (6)(7)(8)(9)(10)(11)(12). Blastocyst formation is therefore essential for the establishment of pregnancy and is intimately coordinated by the events controlling trophectoderm differentiation.…”

“…Although the mouse embryo has been the animal model of choice for most of the experimentation, the e xtension of these studies to the human and domestic agricultural species has stimulated vigorous research activity in these embryo systems leading to explosive growth in the fields of assisted reproductive technology and embryo transfer in humans and other species (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Despite these advances, pregnancy rates following embryo transfer remain lower than expectations for all species, and further advances are required to optimize the general application of these technologies (1)(2)(3)(4)(5)(6).…”

Deletion of the Na/K-ATPase $alpha;1-subunit gene (Atp1a1) does not prevent cavitation of the preimplantation mouse embryo

“…Blastocyst formation (cavitation) is dependent on formation of the trophectoderm epithelium, and is initiated following the establishment of ion gradients and osmotic fluid accumulation across this cell layer (reviewed by Borland, 1977;Wiley, 1984;Biggers et al, 1988;Benos and Balaban, 1990;Watson, 1992;Watson et al, 1999;Watson and Barcroft, 2001). Transporting epithelia utilize the polarized localization of ion transporters and channels within apical and basolateral membrane domains to establish and maintain trans-cellular ion gradients necessary for ion and solute transport, energized by basolateral expression of the Na þ and K þ adenosine triphosphatase (Na/K-ATPase).…”