title: Distinct origins of adult and embryonic blood in Xenopus.
abstract: Whether embryonic and adult blood derive from a single (yolk sac) or dual (yolk sac plus intraembryonic) origin is controversial. Here, we show, in Xenopus, that the yolk sac (VBI) and intraembryonic (DLP) blood compartments derive from distinct blastomeres in the 32-cell embryo. The first adult hematopoietic stem cells (HSCs) are thought to form in association with the floor of the dorsal aorta, and we have detected such aortic clusters in Xenopus using hematopoietic markers. Lineage tracing shows that the aortic clusters derive from the blastomere that gives rise to the DLP. These observations indicate that the first adult HSCs arise independently of the embryonic lineage.
authors.affiliation: Institute of Genetics, University of Nottingham, Queen's Medical Centre, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Ciau-Uitz
authors.forename: M
authors.initials: M
authors.lastname: Walmsley
authors.forename: R
authors.initials: R
authors.lastname: Patient
mesh_terms: D000367:Age Factors; D000818:Animals; D001011:Aorta / Q000166:cytology* / Q000196:embryology* / Q000502:physiology; D001755:Blastocyst / Q000166:cytology / Q000502:physiology; D019070:Cell Lineage / Q000502:physiology; D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000502:physiology; D016228:Endothelial Growth Factors / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D008222:Lymphokines / Q000235:genetics; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000032:analysis; D014157:Transcription Factors / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D014981:Xenopus; D015017:Yolk Sac / Q000098:blood supply* / Q000196:embryology*
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins; D016228:Endothelial Growth Factors; D008222:Lymphokines; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors