title: Identification of a yolk sac cell population with hematopoietic activity in view of CD45/c-Kit expression.
abstract: During murine embryonic development, primitive hematopoiesis occurs in the yolk sac (YS). Recent studies have shown that the YS also harbors definitive hematopoietic activity. However, the population of YS cells contributing to definitive hematopoiesis has not been identified. In this study, we characterized the hematopoietic cell populations in the YS of mouse embryos from E9.5 to E14.5 in view of the expression profiles of CD45 and c-Kit. The YS cells from E9.5 to E11.5 could be divided into six populations: CD45(-) c-Kit(-) , CD45(-) c-Kit(low) , CD45(-) c-Kit(high) , CD45(low) c-Kit(high) , CD45(high) c-Kit(high) and CD45(high) c-Kit(very low) . Among these populations, CD45(low) c-Kit(high) cells showed the highest multilineage hematopoietic colony-forming activity. Later in development, the YS cells from E12.5 to E14.5 lost the second and fourth populations (i.e., they retained CD45(-) c-Kit(-) , CD45(-) c-Kit(high) , CD45(high) c-Kit(high) and CD45(high) c-Kit(very low) cells), and concurrently with the disappearance of the CD45(low) c-Kit(high) population, no significant hematopoietic activity was found in any of the populations on and after E12.5. CD45(low) c-Kit(high) YS cells, which had a round morphology with a large nucleus, possessed the ability to differentiate into myeloid and B lymphoid cells when cultured with stromal cells. These findings suggest that CD45(low) c-Kit(high) YS cells include more undifferentiated cells than the other YS cell populations and possess in vitro potency to differentiate into multilineage hematopoietic cells. Furthermore, this cell population disappears from the YS at around E12.5, when the site of hematopoiesis has already shifted to the fetal liver and the placenta.
authors: Division of Cell Fate Modulation, Institute of Molecular Embryology and Genetics, Graduate School of Pharmaceutical Sciences, Kumamoto University, 2-2-1 Honjo, Kumamoto, Japan.
authors: Shoutarou
authors: S
authors: Yamasaki
authors: Ikuo
authors: I
authors: Nobuhisa
authors: Ahmed
authors: A
authors: Ramadan
authors: Tetsuya
authors: T
authors: Taga
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology; D015415:Biomarkers; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D002469:Cell Separation; D018920:Coculture Techniques; D003114:Colony-Forming Units Assay; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology* / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D050989:GATA2 Transcription Factor / Q000235:genetics / Q000378:metabolism; D006410:Hematopoiesis; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D009000:Monocytes / Q000166:cytology; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism; D015017:Yolk Sac / Q000166:cytology* / Q000378:metabolism
chemical_list: D015415:Biomarkers; D050676:Core Binding Factor Alpha 2 Subunit; D050989:GATA2 Transcription Factor; C494712:Gata2 protein, mouse; C493726:Runx1 protein, mouse; D019009:Proto-Oncogene Proteins c-kit; D017493:Leukocyte Common Antigens; C516770:Ptprc protein, mouse