title: Clonal analysis identifies hemogenic endothelium as the source of the blood-endothelial common lineage in the mouse embryo.
abstract: The first blood and endothelial cells of amniote embryos appear in close association in the blood islands of the yolk sac (YS). This association and in vitro lineage analyses have suggested a common origin from mesodermal precursors called hemangioblasts, specified in the primitive streak during gastrulation. Fate mapping and chimera studies, however, failed to provide strong evidence for a common origin in the early mouse YS. Additional in vitro studies suggest instead that mesodermal precursors first generate hemogenic endothelium, which then generate blood cells in a linear sequence. We conducted an in vivo clonal analysis to determine the potential of individual cells in the mouse epiblast, primitive streak, and early YS. We found that early YS blood and endothelial lineages mostly derive from independent epiblast populations, specified before gastrulation. Additionally, a subpopulation of the YS endothelium has hemogenic activity and displays characteristics similar to those found later in the embryonic hemogenic endothelium. Our results show that the earliest blood and endothelial cell populations in the mouse embryo are specified independently, and that hemogenic endothelium first appears in the YS and produces blood precursors with markers related to definitive hematopoiesis.
authors.affiliation: Departamento de Desarrollo y Reparación Cardiovascular, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Padrón-Barthe
authors.affiliation: Departamento de Desarrollo y Reparación Cardiovascular, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Temiño
authors.affiliation: Departamento de Desarrollo y Reparación Cardiovascular, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Villa del Campo
authors.affiliation: Departamento de Desarrollo y Reparación Cardiovascular, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Carramolino
authors.affiliation: Departamento de Desarrollo y Reparación Cardiovascular, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Isern
authors.affiliation: Departamento de Desarrollo y Reparación Cardiovascular, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Torres
mesh_terms: D000818:Animals; D019070:Cell Lineage; D002999:Clone Cells; D005260:Female; D055018:Hemangioblasts / Q000166:cytology*; D006410:Hematopoiesis; D051379:Mice / Q000196:embryology*; D015017:Yolk Sac / Q000098:blood supply / Q000166:cytology*