Epidermal growth factor receptor function in early mammalian development

Abstract

We review here the data indicating a role for epidermal growth factor receptor (EGF receptor) signalling in early mouse development. Embryonic development of the metazoan embryo generally begins with the formation of a cystic structure and epithelial layers that subsequently form anlagen of the definitive body parts and organs. For the mammalian embryo, this cystic structure is a blastocyst whose wall consists of trophectoderm, the first epithelium to develop during mammalian embryogenesis. The onset of expression and function of EGF receptors is coincident with the onset of trophectoderm development. Modulating EGF receptor expression and function modulates trophectoderm differentiation, leading to the hypothesis that functional EGF receptors participate in the induction of trophectoderm development and perhaps of other embryonic epithelial derivatives such as nervous tissues.

Transforming Growth Factor α Binds to Trypanosoma cruzi Amastigotes To Induce Signaling and Cellular Proliferation

“…3C, exposure of unelicited CBA/J mouse peritoneal macrophages (13) to 2 ng of TGF-␣ per ml and T. cruzi trypomastigotes as described previously (13) induced a significant increase in amastigote replication at 48 h compared to mock-treated macrophages. The major downstream effect of TGF-␣/EGF activation of the EGFR is proliferation of mammalian cells (22). Taken together, these results show that TGF-␣ induces increases in the growth of amastigotes in cell-free media and in macrophages (Fig.…”

“…The concentration of 2 ng/ml was chosen because treatment of amastigotes with different concentrations of TGF-␣ indicated that the tyrosine phosphorylation effect induced by this growth factor is concentration dependent and 2 ng of TGF-␣ per ml induced optimal (highest) phosphorylation (data not shown). Growth factor binding to the EGFR in mammalian cells induces tyrosine phosphorylation (22), including autophosphorylation. Stripping the blots and probing with anti-␤-actin indicated equal loading amounts of amastigote proteins in these blots (Fig.…”

Intracellular Ca2+ Signaling and Preimplantation Development

“…The success of preimplantation development depends on autocrine signaling by a number of trophic factors secreted from embryos. For this reason, embryos cultured as groups in small volumes promptly cleave, and produce blastocysts in greater number than embryos cultured singly in a large volume to dilute any accumulating secretions (Rappolee et al 1988;Paria and Dey 1990;DeChiara et al 1990;Palmieri et al 1992;Schultz and Heyner 1992;Gardner et al 1994;Wiley et al 1995;O'Neill 1997). Embryos cultured in large volumes can, to some extent, be rescued by supplementing them with autocrine factors, including members of the epidermal growth factor (EGF) family and platelet-activating factor (PAF), an ether phospholipid (1-o-alkyl-2-acetyl-sn-glyceryl-3-phosphocholine).…”

Epidermal growth factor family in rhesus monkey uterus during the menstrual cycle and early pregnancy

“…All members of this family are characterized by the presence of one or more EGF structural units in their extracellular domains, and all share some degree of amino acid homology, including the positioning of six conserved cysteines over a sequence of 35-40 amino acids and three disulfide bonds formed by these cysteins (Derynck, 1990;Higashiyama et al, 1992;Wiley et al, 1995;Tsark et al, 1997). They are synthesized as transmembrane proteins and proteolytically processed to release the mature forms (Massague and Pandiella, 1993).…”