Maturation and enucleation of primitive erythroblasts during mouse embryogenesis is accompanied by changes in cell-surface antigen expression.
Primitive erythroblasts (EryPs) are the first hematopoietic cell type to form during mammalian embryogenesis and emerge within the blood islands of the yolk sac. Large, nucleated EryPs begin to circulate around midgestation, when connections between yolk sac and embryonic vasculature mature. Two to 3 days later, small cells of the definitive erythroid lineage (EryD) begin to differentiate within the fetal liver and rapidly outnumber EryPs in the circulation. The development and maturation of EryPs remain poorly defined. Our analysis of embryonic blood at different stages reveals a stepwise developmental progression within the EryP lineage from E9.5 to E12.5. Thereafter, EryDs are also present in the bloodstream, and the 2 lineages are not easily distinguished. We have generated a transgenic mouse line in which the human epsilon-globin gene promoter drives expression of green fluorescent protein exclusively within the EryP lineage. Here, we have used this line to characterize changes in cell morphology and surface-marker expression as EryPs mature and to track EryP numbers and enucleation throughout gestation. This study identifies previously unrecognized synchronous developmental stages leading to the maturation of EryPs in the mouse embryo. Unexpectedly, we find that EryPs are a stable cell population that persists through the end of gestation.
Fraser
Stuart T
ST
Department of Medicine, Mount Sinai School of Medicine, New York, NY, USA.
Isern
Joan
J
Baron
Margaret H
MH
D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D000954:Antigens, Surface / Q000096:biosynthesis* / Q000235:genetics; D001789:Blood Group Antigens / Q000096:biosynthesis / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000096:biosynthesis / Q000235:genetics; D002467:Cell Nucleus; D003433:Crosses, Genetic; D004900:Erythroblasts / Q000166:cytology* / Q000378:metabolism; D004920:Erythropoiesis / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D005914:Globins / Q000032:analysis / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008822:Mice, Transgenic; D017978:Receptors, Growth Factor / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015703:Antigens, CD; D000954:Antigens, Surface; D001789:Blood Group Antigens; D015815:Cell Adhesion Molecules; D017978:Receptors, Growth Factor; C489122:TER-119 antigen, mouse; C485192:green fluorescent protein, Aequorea victoria; D049452:Green Fluorescent Proteins; D005914:Globins