title: Definitive but not primitive hematopoiesis is impaired in jumonji mutant mice.
abstract: A novel gene, jumonji was identified by a mouse gene trap strategy. The jumonji gene encodes a protein containing a putative DNA binding domain. The mice homozygous for jumonji gene with a BALB/cA genetic background show hypoplasia of the fetal liver and embryonic lethality, suggesting impaired hematopoiesis. In the peripheral blood of jumonji mutant embryos, the number of fetal liver-derived definitive erythrocytes, but not yolk sac-derived primitive erythrocytes, showed a marked reduction, suggesting that jumonji mutants die of anemia. The defects of definitive erythrocytes in jumonji mutants seemed to be caused by a decrease in the numbers of multiple hematopoietic progenitors including colony-forming unit-spleen (CFU-S) in the fetal liver. However, hematopoietic stem cells (HSCs) in the fetal liver of jumonji mutants could reconstitute the hematopoietic system of lethally irradiated recipients. In the fetal liver, the jumonji gene is expressed in fibroblastic cells and endothelial cells, but not in Lin-/c-Kit+/Sca-1(+) cells known to include HSCs. These results suggest that an environmental defect induce the impaired hematopoiesis in the fetal liver of jumonji mutant embryos.
authors.affiliation: Mitsubishi Kasei Institute of Life Sciences, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kitajima
authors.forename: M
authors.initials: M
authors.lastname: Kojima
authors.forename: K
authors.initials: K
authors.lastname: Nakajima
authors.forename: S
authors.initials: S
authors.lastname: Kondo
authors.forename: T
authors.initials: T
authors.lastname: Hara
authors.forename: A
authors.initials: A
authors.lastname: Miyajima
authors.forename: T
authors.initials: T
authors.lastname: Takeuchi
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D003114:Colony-Forming Units Assay; D004906:Erythrocyte Count; D004912:Erythrocytes / Q000473:pathology; D018507:Gene Expression Regulation, Developmental; D006410:Hematopoiesis / Q000235:genetics* / Q000528:radiation effects; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000473:pathology; D007958:Leukocyte Count; D008099:Liver / Q000166:cytology / Q000196:embryology / Q000528:radiation effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D009419:Nerve Tissue Proteins / Q000235:genetics*; D063151:Polycomb Repressive Complex 2; D011828:Radiation Chimera; D015017:Yolk Sac / Q000166:cytology / Q000502:physiology
chemical_list: C093650:Jarid2 protein, mouse; D009419:Nerve Tissue Proteins; D063151:Polycomb Repressive Complex 2