Extensive in vivo self-renewal, long-term reconstitution capacity, and hematopoietic multipotency of Pax5-deficient precursor B-cell clones.
Self-renewal, pluripotency, and long-term reconstitution are defining characteristics of single hematopoietic stem cells. Pax5(-/-) precursor B cells apparently possess similar characteristics. Here, using serial transplantations, with in vitro recloning and growth of the bone marrow-homed donor cells occurring after all transplantations, we analyzed the extent of self-renewal and hematopoietic multipotency of Pax5(-/-) precursor B-cell clones. Moreover, telomere length and telomerase activity in these clones was analyzed at various time points. Thus far, 5 successive transplantations have been performed. Clones transplanted for the fifth time, which have proliferated for more than 150 cell divisions in vitro, still repopulate the bone marrow with precursor B cells and reconstitute these recipients with lymphoid and myeloid cells. During this extensive proliferation, Pax5(-/-) precursor B cells shorten their telomeres at 70 to 90 base pairs per division. Their telomerase activity remains at 3% of that of HEK293 cancer cells during all serial in vivo transplantations/in vitro expansions. Together, these data show that Pax5(-/-) precursor B-cell clones possess extensive in vivo self-renewal capacity, long-term reconstitution capacity, and hematopoietic multipotency, with their telomeres shortening at the normal rate.
Schaniel
Christoph
C
Basel Institute for Immunology, Switzerland. schaniel@molbio.princeton.edu
Gottar
Marie
M
Roosnek
Eddy
E
Melchers
Fritz
F
Rolink
Antonius G
AG
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000502:physiology; D001853:Bone Marrow; D002454:Cell Differentiation; D002455:Cell Division; D002465:Cell Movement / Q000502:physiology*; D002999:Clone Cells / Q000166:cytology / Q000502:physiology / Q000637:transplantation; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D051757:PAX5 Transcription Factor; D016615:Telomere / Q000378:metabolism / Q000648:ultrastructure; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics
D004268:DNA-Binding Proteins; D051757:PAX5 Transcription Factor; C497282:Pax5 protein, mouse; D014157:Transcription Factors