Abstract:
:Vertebrate hematopoietic stem cells are derived from vental mesoderm, which is postulated to migrate to both extra- and intraembryonic positions during gastrula and neurula stages. Extraembryonic migration has previously been documented, but the origin and migration of intraembryonic hematopoietic cells have not been visualized. The zebrafish and most other teleosts do not form yolk sac blood islands during early embryogenesis, but instead hematopoiesis occurs solely in a dorsal location known as the intermediate cell mass (IM) or Oellacher. In this report, we have isolated cDNAs encoding zebrafish homologs of the hematopoietic transcription factors GATA-1 and GATA-2 and have used these markers to determine that the IM is formed from mesodermal cells in a posterior-lateral position on the yolk syncytial layer of the gastrula yolk sac. Surprisingly, cells of the IM then migrate anteriorly through most of the body length prior to the onset of active circulation and exit onto the yolk sac. These findings support a hypothesis in which the hematopoietic program of vertebrates is established by variations in homologous migration pathways of extra- and intraembryonic progenitors.
journal_name
Proc Natl Acad Sci U S Aauthors
Detrich HW 3rd,Kieran MW,Chan FY,Barone LM,Yee K,Rundstadler JA,Pratt S,Ransom D,Zon LIdoi
10.1073/pnas.92.23.10713subject
Has Abstractpub_date
1995-11-07 00:00:00pages
10713-7issue
23eissn
0027-8424issn
1091-6490journal_volume
92pub_type
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