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Primitive erythropoiesis and megakaryopoiesis in the yolk sac are independent of c-myb

Hematopoiesis initiates within the yolk sac of mammalian embryos in overlapping primitive and definitive waves, each containing erythroid and megakaryocyte progenitors. c-myb–null mouse fetuses lack definitive erythrocytes but contain primitive erythroblasts and hepatic megakaryocytes. However, it i...

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Bibliographic Details
Published in:Blood 2008-03, Vol.111 (5), p.2636-2639
Main Authors: Tober, Joanna, McGrath, Kathleen E., Palis, James
Format: Article
Language:English
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Summary:Hematopoiesis initiates within the yolk sac of mammalian embryos in overlapping primitive and definitive waves, each containing erythroid and megakaryocyte progenitors. c-myb–null mouse fetuses lack definitive erythrocytes but contain primitive erythroblasts and hepatic megakaryocytes. However, it is unclear if c-myb–null embryos harbor definitive erythroid or any megakaryocyte progenitors. We determined that c-myb was not expressed in primitive erythroid precursors and that c-myb–null embryos had normal primitive erythroid and megakaryocyte progenitor numbers and kinetics between embryonic day (E) 7.0 and E9.0. While primitive hematopoiesis is c-myb–independent, no definitive erythroid potential was detected in c-myb–null embryos, confirming that definitive erythropoiesis, beginning at E8.25 in the yolk sac, is completely c-myb–dependent. In contrast, reduced numbers of megakaryocyte progenitors with restricted proliferative capacity persist in E10.5 yolk sac and E11.5 liver. Despite this impaired megakaryocyte potential, c-myb–null fetuses had normal platelet numbers at E12.5 but became thrombocytopenic by E15.5, suggesting that c-myb is required for sustained thrombopoiesis.
ISSN:0006-4971
1528-0020
DOI:10.1182/blood-2007-11-124685