Localization of Brachyury (T) in embryonic and extraembryonic tissues during mouse gastrulation.
T-box gene family members have important roles during murine embryogenesis, gastrulation, and organogenesis. Although relatively little is known about how T-box genes are regulated, published gene expression studies have revealed dynamic and specific patterns in both embryonic and extraembryonic tissues of the mouse conceptus. Mutant alleles of the T-box gene Brachyury (T) have identified roles in formation of mesoderm and its derivatives, such as somites and the allantois. However, given the cell autonomous nature of T gene activity and conflicting results of gene expression studies, it has been difficult to attribute a primary function to T in normal allantoic development. We report localization of T protein by sectional immunohistochemistry in both embryonic and extraembryonic tissues during mouse gastrulation, emphasizing T localization within the allantois. T was detected in all previously reported sites within the conceptus, including the primitive streak and its derivatives, nascent embryonic mesoderm, the node and notochord, as well as notochord-associated endoderm and posterior neurectoderm. In addition, we have clarified T within the allantois, where it was first detected in the proximal midline of the late allantoic bud (approximately 7.5 days postcoitum, dpc) and persisted within an expanded midline domain until 6-somite pairs (s; approximately 8.5 dpc). Lastly, we have discovered several novel T sites, including the developing heart, visceral endoderm, extraembryonic ectoderm, and its derivative, chorionic ectoderm. Together, these data provide a unified picture of T in the mammalian conceptus, and demonstrate T's presence in unrelated cell types and tissues in highly dynamic spatiotemporal patterns in both embryonic and extraembryonic tissues.
Department of Anatomy, University of Wisconsin - Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA.
Kimberly E
KE
Inman
Karen M
KM
Downs
D000482:Allantois / Q000378:metabolism; D000818:Animals; D000918:Antibody Specificity; D002823:Chorion / Q000378:metabolism; D004475:Ectoderm / Q000378:metabolism; D004622:Embryo, Mammalian / Q000378:metabolism; D047108:Embryonic Development / Q000502:physiology; D004628:Embryonic Structures / Q000378:metabolism; D005326:Fetal Proteins / Q000378:metabolism*; D005775:Gastrula / Q000378:metabolism*; D006321:Heart / Q000196:embryology; D051379:Mice / Q000196:embryology*; D009206:Myocardium / Q000378:metabolism; D009672:Notochord / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000378:metabolism*; D014018:Tissue Distribution; D014781:Viscera / Q000196:embryology / Q000378:metabolism; D000098908:Brachyury Protein
D005326:Fetal Proteins; D020825:T-Box Domain Proteins; D000098908:Brachyury Protein