Mapping and expression analysis of the mouse ortholog of Xenopus Eomesodermin

Abstract

The T-box gene family has been conserved throughout metazoan evolution. The genes code for putative transcription factors which share a uniquely defining DNA binding domain, known as the T-box ([Bollag et al., 1994]). They are implicated in the control of diverse developmental processes by their highly specific expression patterns throughout gastrulation and organogenesis in mouse and other species ([Chapman et al., 1996]) ([Gibson-Brown et al., 1998]), and by mutations in T-box genes that have profound developmental effects ([Papaioannou, 1997]; [Chapman and Papaioannou, 1998]; [Papaioannou and Silver, 1998]). In this report, we describe the mapping and expression pattern of the mouse ortholog of a gene, Eomesodermin, first identified in Xenopus ([Ryan et al., 1996]). The mouse gene was previously reported ([Wattler et al., 1998]) under the name MmEomes. The gene maps to mouse chromosome 9 in a region syntenic with human chromosome 3p. Mouse eomesodermin is expressed in the trophoblast of the blastocyst and in its derivative, the chorionic ectoderm. At gastrulation, eomesodermin is expressed in the primitive streak and embryonic mesoderm as well, but this expression disappears prior to the end of gastrulation. Later, eomesodermin is expressed in the developing forebrain, in a pattern largely overlapping a closely related T-box gene, Tbr1 ([Bulfone et al., 1995]), and is also seen in a localized area of each limb.

Staging of ovine embryos and expression of the T-box genes Brachyury and Eomesodermin around gastrulation

“…Eomes was first detected in the extra-embryonic epiblast prior to gastrulation and in the embryo proper at the ES stage, thereafter expression declines to be renewed in the forebrain and limbs at days 12.5-14.5 (Bulfone et al 1999, Ciruna & Rossant 1999, Hancock et al 1999. Overall, Eomes expression in the gastrulating ovine embryo fits the cellular pattern of expression described in the mouse.…”

“…The members of the T-box gene family, which encode transcription factors, are highly conserved and play important roles in the development of both vertebrate and invertebrate embryos (Hermann & Kispert 1994, Papaioannou & Silver 1998, Smith 1999. At least two T-box genes, Brachyury (bra) and Eomesodermin (Eomes), have been shown to play major roles in the primitive streak formation and mesoderm patterning in the mouse (Hermann et al 1990, Wilkinson et al 1990, Ciruna & Rossant 1999, Hancock et al 1999, Xenopus (Ryan et al 1996) and chicken (Bulfone et al 1999). bra is one of the first morphogenetic mutants identified in the mouse.…”

T‐box genes in early embryogenesis

“…In the mouse, for example, Eomesodermin is expressed in mesodermal tissues, including the prospective mesoderm of the epiblast layer, the primitive streak, and the nascent mesoderm, as well as in extra-embryonic tissues such as the trophoblasts (Ciruna and Rossant, 1999;Hancock et al, 1999;Russ et al, 2000). Genetic analysis of mutant mice shows that, like Brachyury, Eomesodermin is required cell autonomously within the tissues that normally express the gene.…”

Pre-Implantation Conceptus and Maternal Uterine Communications: Molecular Events Leading to Successful Implantation

“…It is generally believed that transcription factors play critical roles in promoting and driving this first differentiation. Numerous transcription factors are expressed in trophoblasts, including Rex-1 [1], GATA-3 [2], T-box gene Eomesodermin (Eomes) [3,4], the caudal-related gene Cdx-2 [5], activating protein 2 gamma (AP-2γ) [6,7], basic helix-loophelix (bHLH) gene Mash2 [8] and Hand1 [9], and Ets-2 [10]. The T-box gene Eomes and homeobox gene Cdx-2 are required for early trophoblast development during the pre-implantation period [11,12].…”

“…Conceptus IFN-τ binds to a type I IFN receptor (IFNAR) located on luminal epithelial cells of the endometrium [105][106][107], and reduces the numbers of ER and oxytocin receptor (OXY-R) [108][109][110]. This binding eventually results in the attenuation of endometrial PGF 2α secretion, which leads to CL maintenance and continued production of P 4 .…”