title: Identity and fate of Tbx4-expressing cells reveal developmental cell fate decisions in the allantois, limb, and external genitalia.
abstract: T-box gene Tbx4 is critical for the formation of the umbilicus and the initiation of the hindlimb. Previous studies show broad expression in the allantois, hindlimb, lung and proctodeum. We have examined the expression of Tbx4 in detail and used a Tbx4-Cre line to trace the fates of Tbx4-expressing cells. Tbx4 expression and lineage reveal that various distinct appendages, such as the allantois, hindlimb, and external genitalia, all arise from a single mesenchymal expression domain. Additionally, although Tbx4 is associated primarily with the hindlimb, we find two forelimb expression domains. Most notably, we find that, despite the requirement for Tbx4 in allantoic vasculogenesis, the presumptive endothelial cells of the allantois do not express Tbx4 and lineage tracing reveals that the umbilical vasculature never expresses Tbx4. These results suggest that endothelial lineages are segregated before the onset of vasculogenesis, and demonstrate a role for the peri-vascular tissue in vasculogenesis.
authors.affiliation: Cancer and Developmental Biology Lab, National Cancer Institute - Frederick, Frederick, Maryland, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Naiche
authors.forename: Ripla
authors.initials: R
authors.lastname: Arora
authors.forename: Artur
authors.initials: A
authors.lastname: Kania
authors.forename: Mark
authors.initials: M
authors.lastname: Lewandoski
authors.forename: Virginia E
authors.initials: VE
authors.lastname: Papaioannou
mesh_terms: D000482:Allantois / Q000166:cytology* / Q000196:embryology* / Q000502:physiology; D000818:Animals; D019070:Cell Lineage; D004622:Embryo, Mammalian / Q000033:anatomy & histology / Q000502:physiology; D005121:Extremities / Q000033:anatomy & histology / Q000196:embryology* / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005835:Genitalia / Q000166:cytology / Q000196:embryology* / Q000502:physiology; D008297:Male; D008648:Mesoderm / Q000166:cytology / Q000502:physiology; D051379:Mice; D009024:Morphogenesis; D011247:Pregnancy; D020825:T-Box Domain Proteins / Q000235:genetics / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D020825:T-Box Domain Proteins; C103177:Tbx4 protein, mouse