Pax-5 and EBF are expressed in committed B-cell progenitors prior to the colonization of the embryonic bursa of fabricius.
The committed B-cell precursors developing from hemopoietic stem cells have been considered to differentiate through a common lymphoid progenitor stage in the mouse. In the chicken B-cell system, however, the committed B-cell progenitors burst as a single wave prior to the bursal colonization and most likely as direct descendants of hemopoietic stem cells. In the present report we show that prebursally committed B-cell progenitors specifically express early B-cell factor (EBF) and Pax-5 transcription factors. In addition we show that the expression of these and other B-lineage-associated transcription factors starts early in the chicken ontogeny. Altogether our findings strongly support the model of early delineation of B- and T-cell development and do not support the existence of common lymphoid stem cells.
Nieminen
P
P
Turku Graduate School of Biomedical Sciences, Department of Medical Microbiology, University of Turku, Kiinamyllynkatu 13, FIN-20520 Turku, Finland. pia.nieminen@utu.fi
Liippo
J
J
Lassila
O
O
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology*; D002060:Bursa of Fabricius / Q000196:embryology*; D019070:Cell Lineage; D002642:Chick Embryo; D002645:Chickens / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D008221:Lymphoid Tissue / Q000196:embryology; D018448:Models, Immunological; D009687:Nuclear Proteins / Q000378:metabolism; D051757:PAX5 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D004268:DNA-Binding Proteins; C489921:Ebf1 protein, mouse; D009687:Nuclear Proteins; D051757:PAX5 Transcription Factor; D015534:Trans-Activators; D014157:Transcription Factors