The early ontogeny of hematopoietic cells studied by grafting cytogenetically labeled tissue anlagen: Localization of a prospective stem cell compartment☆

[摘要] Therelativecontributionsofventralbloodislandmesodermanddorsalanteriormesodermtodifferentiatedlineagesofhematopoieticcellswasassessedbyreciprocalgraftingofcytogeneticallylabeledtissuesbetween67-and72-hr-oldfrogembryos(Shumwaystages15–16).Diploid(2N)andtriploid(3N)cellpopulationsfromhematopoieticorgansweredistinguishedbyFeulgen-DNAmicrodensitometricanalysis.Ventralbloodislandmesodermappearstocontributeanembryonicerythrocytepopulationthatprogressivelydeclinesduringlarvaldevelopment.Dorsalanteriormesodermappearstocontributeapopulationofprecursorcellsthatgivesrisetodifferentiatedlineagesofhematopoieticcellsfoundinthethymus,pronephros,mesonephros,spleen,andblood.Histologicalexaminationofthedevelopingdorsalanteriorareaindicatesthatextensivevascularizationisaprominentcharacteristicofthisregion.Thedorsalaortaeandvasculaturesurroundingthepronephrosmaybesiteswhereatleastonepopulationofhematopoieticcellsmaturesandsubsequentlyenterscirculation.

[学科分类] 生物科学（综合）