Limits...
Polycomb group gene rae28 is required for sustaining activity of hematopoietic stem cells.

Ohta H, Sawada A, Kim JY, Tokimasa S, Nishiguchi S, Humphries RK, Hara J, Takihara Y - J. Exp. Med. (2002)

Bottom Line: CRUs were generated, whereas the number of CRUs was reduced by a factor of 20 in the rae28-/- fetal liver.Self-renewal activity of CRUs was 15-fold decreased in rae28-/-.Thus the compromised HSCs were presumed to reduce hematopoietic activity in the rae28-/- fetal liver.

View Article: PubMed Central - PubMed

Affiliation: Department of Developmental Biology and Medicine, Osaka Medical Center for Cancer and Cardiovascular Diseases, 3-3 Nakamichi-1, Higashinari, Osaka 537-8511, Japan.

ABSTRACT
The rae28 gene (rae28), also designated as mph1, is a mammalian ortholog of the Drosophila polyhomeotic gene, a member of Polycomb group genes (PcG). rae28 constitutes PcG complex 1 for maintaining transcriptional states which have been once initiated, presumably through modulation of the chromatin structure. Hematopoietic activity was impaired in the fetal liver of rae28-deficient animals (rae28-/-), as demonstrated by progressive reduction of hematopoietic progenitors of multilineages and poor expansion of colony forming units in spleen (CFU-S(12)) during embryonic development. An in vitro long-term culture-initiating cell assay suggested a reduction in hematopoietic stem cells (HSCs), which was confirmed in vivo by reconstitution experiments in lethally irradiated congenic recipient mice. The competitive repopulating units (CRUs) reflect HSCs supporting multilineage blood-cell production. CRUs were generated, whereas the number of CRUs was reduced by a factor of 20 in the rae28-/- fetal liver. We also performed serial transplantation experiments to semiquantitatively measure self-renewal activity of CRUs in vivo. Self-renewal activity of CRUs was 15-fold decreased in rae28-/-. Thus the compromised HSCs were presumed to reduce hematopoietic activity in the rae28-/- fetal liver. This is the first report to suggest that rae28 has a crucial role in sustaining the activity of HSCs to maintain hematopoiesis.

Show MeSH

Related in: MedlinePlus

Cell cycle status of fetal liver cells. Cells were pulse-labeled with 10 μg/ml BrdU after harvest, stained with PI, and subjected to FACS® analysis. Representative BrdU-FITC/PI fluorescence profiles of wild-type and rae28−/− fetal liver cells are shown in the Figure. +/+, wild-type; −/−, rae28−/−.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2193743&req=5

fig6: Cell cycle status of fetal liver cells. Cells were pulse-labeled with 10 μg/ml BrdU after harvest, stained with PI, and subjected to FACS® analysis. Representative BrdU-FITC/PI fluorescence profiles of wild-type and rae28−/− fetal liver cells are shown in the Figure. +/+, wild-type; −/−, rae28−/−.

Mentions: To examine whether hematopoietic defects in the rae28−/− fetal liver reflected an impaired proliferation of fetal liver cells, we examined the cell cycle status of 14.5 dpc fetal liver cells. The relative DNA content of the fetal liver cells was assessed with PI staining, whereas BrdU incorporation by the cells was measured after in vitro BrdU pulse labeling for 1 h of the isolated cells. As shown in Fig. 6, no significant difference in cycling parameters was evident.


Polycomb group gene rae28 is required for sustaining activity of hematopoietic stem cells.

Ohta H, Sawada A, Kim JY, Tokimasa S, Nishiguchi S, Humphries RK, Hara J, Takihara Y - J. Exp. Med. (2002)

Cell cycle status of fetal liver cells. Cells were pulse-labeled with 10 μg/ml BrdU after harvest, stained with PI, and subjected to FACS® analysis. Representative BrdU-FITC/PI fluorescence profiles of wild-type and rae28−/− fetal liver cells are shown in the Figure. +/+, wild-type; −/−, rae28−/−.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2193743&req=5

fig6: Cell cycle status of fetal liver cells. Cells were pulse-labeled with 10 μg/ml BrdU after harvest, stained with PI, and subjected to FACS® analysis. Representative BrdU-FITC/PI fluorescence profiles of wild-type and rae28−/− fetal liver cells are shown in the Figure. +/+, wild-type; −/−, rae28−/−.
Mentions: To examine whether hematopoietic defects in the rae28−/− fetal liver reflected an impaired proliferation of fetal liver cells, we examined the cell cycle status of 14.5 dpc fetal liver cells. The relative DNA content of the fetal liver cells was assessed with PI staining, whereas BrdU incorporation by the cells was measured after in vitro BrdU pulse labeling for 1 h of the isolated cells. As shown in Fig. 6, no significant difference in cycling parameters was evident.

Bottom Line: CRUs were generated, whereas the number of CRUs was reduced by a factor of 20 in the rae28-/- fetal liver.Self-renewal activity of CRUs was 15-fold decreased in rae28-/-.Thus the compromised HSCs were presumed to reduce hematopoietic activity in the rae28-/- fetal liver.

View Article: PubMed Central - PubMed

Affiliation: Department of Developmental Biology and Medicine, Osaka Medical Center for Cancer and Cardiovascular Diseases, 3-3 Nakamichi-1, Higashinari, Osaka 537-8511, Japan.

ABSTRACT
The rae28 gene (rae28), also designated as mph1, is a mammalian ortholog of the Drosophila polyhomeotic gene, a member of Polycomb group genes (PcG). rae28 constitutes PcG complex 1 for maintaining transcriptional states which have been once initiated, presumably through modulation of the chromatin structure. Hematopoietic activity was impaired in the fetal liver of rae28-deficient animals (rae28-/-), as demonstrated by progressive reduction of hematopoietic progenitors of multilineages and poor expansion of colony forming units in spleen (CFU-S(12)) during embryonic development. An in vitro long-term culture-initiating cell assay suggested a reduction in hematopoietic stem cells (HSCs), which was confirmed in vivo by reconstitution experiments in lethally irradiated congenic recipient mice. The competitive repopulating units (CRUs) reflect HSCs supporting multilineage blood-cell production. CRUs were generated, whereas the number of CRUs was reduced by a factor of 20 in the rae28-/- fetal liver. We also performed serial transplantation experiments to semiquantitatively measure self-renewal activity of CRUs in vivo. Self-renewal activity of CRUs was 15-fold decreased in rae28-/-. Thus the compromised HSCs were presumed to reduce hematopoietic activity in the rae28-/- fetal liver. This is the first report to suggest that rae28 has a crucial role in sustaining the activity of HSCs to maintain hematopoiesis.

Show MeSH
Related in: MedlinePlus