A role of jumonji gene in proliferation but not differentiation of megakaryocyte lineage cells.
In this study, megakaryocytopoiesis was investigated in the recessive mutant mouse, jumonji, obtained by a gene-trap strategy. We investigated the number of megakaryocyte progenitors in the fetal liver, yolk sac, and peripheral blood of jumonji homozygous embryos by in vitro colony forming assay and monitored colony formation from single megakaryocyte progenitors. We also investigated the differentiation of jumonji-deficient megakaryocytes in terms of the expression of megakaryocyte differentiation markers PF4, CD62P, and GATA-1, proplatelet formation, cytoplasmic maturation, and endomitosis. We found that the population of megakaryocyte progenitors in the fetal liver, yolk sac, and peripheral blood of jumonji homozygotes increased. A fraction of megakaryocyte progenitors derived from the fetal liver of jumonji homozygotes formed larger colonies in vitro when compared with controls. This abnormality is caused by delayed growth arrest in the progeny. Immature megakaryocyte progenitors showed this abnormality. The megakaryocytes of jumonji homozygotes expressed PF4, CD62P, and GATA-1, obtained cytoplasmic maturation, extended proplatelet-like processes, and underwent endomitosis. The loss of the jumonji gene causes an increase in the number of megakaryocyte lineage cells. Our data suggest that the jumonji gene regulates proliferation but not differentiation of megakaryocyte lineage cells.
Kitajima
K
K
Mitsubishi Kasei Institute of Life Sciences, 11, Minamiooya, Machida, Tokyo 194-8511, Japan.
Kojima
M
M
Kondo
S
S
Takeuchi
T
T
D000818:Animals; D002452:Cell Count; D002454:Cell Differentiation; D002455:Cell Division; D003114:Colony-Forming Units Assay; D004268:DNA-Binding Proteins / Q000032:analysis; D050981:Erythroid-Specific DNA-Binding Factors; D005260:Female; D050982:GATA1 Transcription Factor; D006412:Hematopoietic Stem Cells / Q000166:cytology; D006720:Homozygote; D008099:Liver / Q000166:cytology / Q000196:embryology; D008297:Male; D008533:Megakaryocytes / Q000166:cytology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000172:deficiency* / Q000235:genetics / Q000502:physiology*; D019007:P-Selectin / Q000032:analysis; D010978:Platelet Factor 4 / Q000032:analysis; D063151:Polycomb Repressive Complex 2; D013926:Thrombopoietin / Q000494:pharmacology; D014157:Transcription Factors / Q000032:analysis; D015017:Yolk Sac / Q000166:cytology / Q000196:embryology
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494689:Gata1 protein, mouse; C093650:Jarid2 protein, mouse; D009419:Nerve Tissue Proteins; D019007:P-Selectin; D014157:Transcription Factors; D010978:Platelet Factor 4; D013926:Thrombopoietin; D063151:Polycomb Repressive Complex 2