Genes and signals regulating murine trophoblast cell development

Abstract

A fundamental step in embryonic development is cell differentiation whereby highly specialised cell types are developed from a single undifferentiated, fertilised egg. One of the earliest lineages to form in the mammalian conceptus is the trophoblast, which contributes exclusively to the extraembryonic structures that form the placenta. Trophoblast giant cells (TGCs) in the rodent placenta form the outermost layer of the extraembryonic compartment, establish direct contact with maternal cells, and produce a number of pregnancy-specific cytokine hormones. Giant cells differentiate from proliferative trophoblasts as they exit the cell cycle and enter a genome-amplifying endocycle. Normal differentiation of secondary TGCs is a critical step toward the formation of the placenta and normal embryonic development. Trophoblast development is also of particular interest to the developmental biologist and immunobiologist, as these cells constitute the immediate cellular boundary between the embryonic and maternal tissues. Abnormalities in the development of secondary TGCs results in severe malfunction of the placenta. Herein we review new information that has been accumulated recently regarding the molecular and cellular regulation of trophoblast and placenta development. In particular, we discuss the molecular aspects of murine TGC differentiation. We also focus on the role of growth and transcription factors in TGC development.

Rat placentation: An experimental model for investigating the hemochorial maternal-fetal interface

“…Positive selection has resulted in the conservation of genes regulating mammalian placentation [9–13]. The mouse has been a valuable animal model for studying many aspects of placentation [13–15]; however, in contrast to the human, intrauterine trophoblast invasion is shallow and placentation superficial [16–18]. Organization of rat and human placentation sites exhibit striking similarities (Fig.…”

The mouse KRAB zinc-finger protein CHATO is required in embryonic-derived tissues to control yolk sac and placenta morphogenesis

“…More than 90 genes have been described to affect the development of these extraembryonic tissues (for a comprehensive review of mouse mutants with placental phenotypes see Inman and Downs, 2007; Watson and Cross, 2005). Some mutations affect differentiation of extraembryonic cell types: for instance, transcription factors Achaete-Scute complex homolog-2 (ASCL2) and Heart and neural crest derivatives expressed transcript-1 (HAND1) regulate the differentiation of trophoblast giant cells from TE stem cell precursors (El-Hashash et al, 2010; Hu and Cross, 2010). Other mutants affect extraembryonic mesoderm cells or their derivatives, as in the case of mutations in Brachyury ( T ) and Bone morphogenetic protein (Bmp) signaling, which affect extraembryonic mesoderm morphogenesis and the formation of the allantois (Downs et al, 2004; Inman and Downs, 2006; Rashbass et al, 1991; Tremblay et al, 2001; Winnier et al, 1995).…”

Dynamic Pattern of HOXB9 Protein Localization during Oocyte Maturation and Early Embryonic Development in Mammals

“…Extra-embryonic ectodermal (ExE) cells were also devoid of staining (Fig 5A1). Primary trophoblastic giant cells (TGCIs), derived from the mural TE cells undergoing endoreduplication [65], also presented a strong nuclear staining (Fig 5A2). Conversely, HOXB9 was barely detected in epiblast cells (Fig 5A1 –section a).…”