scholarly journals Dissecting Regulatory Mechanisms Using Mouse Fetal Liver-Derived Erythroid Cells

Author(s):  
Skye C. McIver ◽  
Kyle J. Hewitt ◽  
Xin Gao ◽  
Charu Mehta ◽  
Jing Zhang ◽  
...  
Blood ◽  
1984 ◽  
Vol 64 (4) ◽  
pp. 930-936 ◽  
Author(s):  
I Max-Audit ◽  
U Testa ◽  
D Kechemir ◽  
M Titeux ◽  
W Vainchenker ◽  
...  

To further investigate the erythroid nature of the two human erythroleukemia cell lines, K562 and HEL-60, and to define the ontogeny of pyruvate kinase (PK) isozymes (R, M2) in developing human erythroid cells, we have studied the isozymic alterations, if any, during differentiation of these cell lines in vitro and normoblasts isolated from fetal liver in vivo. PK activity of erythroleukemic cell lines was intermediate between that observed in leukocytes and in fetal liver erythroblasts. These cell lines contained a high level of M2-PK, but R- PK was always present, albeit at low concentrations, in all the clones or subclones we studied. Erythroblasts from fetal liver were separated according to density on a Stractan gradient. R-PK levels were nearly constant in the different fractions, whereas M2-PK levels markedly decreased as the erythroblasts became mature and almost completely disappeared in late erythroid cells. Thus, these results clearly demonstrate the erythroid origin of these cell lines.


Blood ◽  
1998 ◽  
Vol 91 (2) ◽  
pp. 695-705 ◽  
Author(s):  
Lingyun Zhu ◽  
Samir B. Kahwash ◽  
Long-Sheng Chang

Abstract Erythrocyte protein 4.2 (P4.2) is an important component of the erythrocyte membrane skeletal network with an undefined biologic function. Presently, very little is known about the expression of the P4.2 gene during mouse embryonic development and in adult animals. By using the Northern blot and in situ hybridization techniques, we have examined the spatial and temporal expression of the P4.2 gene during mouse development. We show that expression of the mouse P4.2 gene is temporally regulated during embryogenesis and that the P4.2 mRNA expression pattern coincides with the timing of erythropoietic activity in hematopoietic organs. P4.2 transcripts are first detected in embryos on day 7.5 of gestation and are localized exclusively in primitive erythroid cells of yolk sac origin. These erythroid cells remain to be the only source for P4.2 expression until the switch of the hematopoietic producing site to fetal liver. In mid- and late-gestation periods, P4.2 mRNA expression is restricted to the erythroid cells in fetal liver and to circulating erythrocytes. Around and after birth, the site for P4.2 expression is switched from liver to spleen and bone marrow, and P4.2 transcripts are only detected in cells of the erythroid lineage. These results provide the evidence for specific P4.2 expression in erythroid cells. In addition, the timing and pattern of expression of the P4.2 gene suggest the specific regulation of the P4.2 gene.


Blood ◽  
2006 ◽  
Vol 108 (5) ◽  
pp. 1515-1523 ◽  
Author(s):  
Kai-Hsin Chang ◽  
Angelique M. Nelson ◽  
Hua Cao ◽  
Linlin Wang ◽  
Betty Nakamoto ◽  
...  

Human embryonic stem cells are a promising tool to study events associated with the earliest ontogenetic stages of hematopoiesis. We describe the generation of erythroid cells from hES (H1) by subsequent processing of cells present at early and late stages of embryoid body (EB) differentiation. Kinetics of hematopoietic marker emergence suggest that CD45+ hematopoiesis peaks at late D14EB differentiation stages, although low-level CD45- erythroid differentiation can be seen before that stage. By morphologic criteria, hES-derived erythroid cells were of definitive type, but these cells both at mRNA and protein levels coexpressed high levels of embryonic (ϵ) and fetal (γ) globins, with little or no adult globin (β). This globin expression pattern was not altered by the presence or absence of fetal bovine serum, vascular endothelial growth factor, Flt3-L, or coculture with OP-9 during erythroid differentiation and was not culture time dependent. The coexpression of both embryonic and fetal globins by definitive-type erythroid cells does not faithfully mimic either yolk sac embryonic or their fetal liver counterparts. Nevertheless, the high frequency of erythroid cells coexpressing embryonic and fetal globin generated from embryonic stem cells can serve as an invaluable tool to further explore molecular mechanisms.


1988 ◽  
Vol 106 (3) ◽  
pp. 649-656 ◽  
Author(s):  
L Morris ◽  
P R Crocker ◽  
S Gordon

During mammalian development the fetal liver plays an important role in hematopoiesis. Studies with the macrophage (M phi)-specific mAb F4/80 have revealed an extensive network of M phi plasma membranes interspersed between developing erythroid cells in fetal liver. To investigate the interactions between erythroid cells and stromal M phi, we isolated hematopoietic cell clusters from embryonic day-14 murine fetal liver by collagenase digestion and adherence. Clusters of erythroid cells adhered to glass mainly via M phi, 94% of which bound 19 +/- 11 erythroblasts (Eb) per cell. Bound Eb proliferated vigorously on the surface of fetal liver M phi, with little evidence of ingestion. The M phi could be stripped of their associated Eb and the clusters then reconstituted by incubation with Eb in the presence of divalent cations. The interaction required less Ca++ than Mg++, 100 vs. 250 microM for half-maximal binding, and was mediated by a trypsin-sensitive hemagglutinin on the M phi surface. After trypsin treatment fetal liver M phi recovered the ability to bind Eb and this process could be selectively inhibited by cycloheximide. Inhibition tests showed that the Eb receptor differs from known M phi plasma membrane receptors and fetal liver M phi did not bind sheep erythrocytes, a ligand for a distinct M phi hemagglutinin. We propose that fetal liver M phi interact with developing erythroid cells by a novel nonphagocytic surface hemagglutinin which is specific for a ligand found on Eb and not on mature red cells.


Blood ◽  
1984 ◽  
Vol 64 (4) ◽  
pp. 930-936 ◽  
Author(s):  
I Max-Audit ◽  
U Testa ◽  
D Kechemir ◽  
M Titeux ◽  
W Vainchenker ◽  
...  

Abstract To further investigate the erythroid nature of the two human erythroleukemia cell lines, K562 and HEL-60, and to define the ontogeny of pyruvate kinase (PK) isozymes (R, M2) in developing human erythroid cells, we have studied the isozymic alterations, if any, during differentiation of these cell lines in vitro and normoblasts isolated from fetal liver in vivo. PK activity of erythroleukemic cell lines was intermediate between that observed in leukocytes and in fetal liver erythroblasts. These cell lines contained a high level of M2-PK, but R- PK was always present, albeit at low concentrations, in all the clones or subclones we studied. Erythroblasts from fetal liver were separated according to density on a Stractan gradient. R-PK levels were nearly constant in the different fractions, whereas M2-PK levels markedly decreased as the erythroblasts became mature and almost completely disappeared in late erythroid cells. Thus, these results clearly demonstrate the erythroid origin of these cell lines.


1986 ◽  
Vol 6 (4) ◽  
pp. 1108-1116 ◽  
Author(s):  
M Yagi ◽  
R Gelinas ◽  
J T Elder ◽  
M Peretz ◽  
T Papayannopoulou ◽  
...  

The human alpha-like globins undergo a switch from the embryonic zeta-chain to the alpha-chain early in human development, at approximately the same time as the beta-like globins switch from the embryonic epsilon-to the fetal gamma-chains. We investigated the chromatin structure of the human alpha-globin gene cluster in fetal and adult erythroid cells. Our results indicate that DNase I-hypersensitive sites exist at the 5' ends of the alpha 1- and alpha 2-globin genes as well as at several other sites in the cluster in all erythroid cells examined. In addition, early and late fetal liver erythroid cells and adult bone marrow cells contain hypersensitive sites at the 5' end of the zeta gene, and in a purified population of 130-day-old fetal erythroid cells, the entire zeta-to alpha-globin region is sensitive to DNase I digestion. The presence of features of active chromatin in the zeta-globin region in fetal liver and adult bone marrow cells led us to investigate the transcription of zeta in these cells. By nuclear runoff transcription studies, we showed that initiated polymerases are present on the zeta-globin gene in these normal erythroid cells. Immunofluorescence with anti-zeta-globin antibodies also showed that late fetal liver cells contain zeta-globin. These findings demonstrate that expression of the embryonic zeta-globin continues at a low level in normal cells beyond the embryonic to fetal globin switch.


1977 ◽  
Vol 55 (5) ◽  
pp. 571-575 ◽  
Author(s):  
L. F. Congote ◽  
F. Bruno ◽  
S. Solomon

α-Fetoprotein and the synthesis of heme associated with hemoglobin were measured simultaneously in short-term cultures of human fetal liver cells to correlate the relationship of α-fetoprotein to erythroid cell function. Both synthetic processes decreased exponentially during the first 5 days of culture. The use of media supplemented with different batches of fetal calf serum and porcine portal vein serum indicated that the optimal conditions for the production of α-fetoprotein were different from those required for the synthesis of heme associated with hemoglobin. Moreover, the α-fetoprotein-producing cells could be separated from erythroid cells after velocity sedimentation in Ficoll gradients. Although it is well known that erythropoiesis and α-fetoprotein production occur simultaneously during ontogenesis, α-fetoprotein itself (0.01–100 μg/ml) did not stimulate heme synthesis in liver erythroid cells. Erythropoietin did not stimulate α-fetoprotein production. It is concluded that there is no cause–effect relationship between α-fetoprotein production and erythroid cell function in human fetal liver cells and that the two processes occur independently in different cell types.


Blood ◽  
2007 ◽  
Vol 110 (4) ◽  
pp. 1343-1352 ◽  
Author(s):  
Rodwell Mabaera ◽  
Christine A. Richardson ◽  
Kristin Johnson ◽  
Mei Hsu ◽  
Steven Fiering ◽  
...  

AbstractThe mechanisms underlying the human fetal-to-adult β-globin gene switch remain to be determined. While there is substantial experimental evidence to suggest that promoter DNA methylation is involved in this process, most data come from studies in nonhuman systems. We have evaluated human γ- and β-globin promoter methylation in primary human fetal liver (FL) and adult bone marrow (ABM) erythroid cells. Our results show that, in general, promoter methylation and gene expression are inversely related. However, CpGs at −162 of the γ promoter and −126 of the β promoter are hypomethylated in ABM and FL, respectively. We also studied γ-globin promoter methylation during in vitro differentiation of erythroid cells. The γ promoters are initially hypermethylated in CD34+ cells. The upstream γ promoter CpGs become hypomethylated during the preerythroid phase of differentiation and are then remethylated later, during erythropoiesis. The period of promoter hypomethylation correlates with transient γ-globin gene expression and may explain the previously observed fetal hemoglobin production that occurs during early adult erythropoiesis. These results provide the first comprehensive survey of developmental changes in human γ- and β-globin promoter methylation and support the hypothesis that promoter methylation plays a role in human β-globin locus gene switching.


1998 ◽  
Vol 18 (11) ◽  
pp. 6634-6640 ◽  
Author(s):  
Denise E. Sabatino ◽  
Amanda P. Cline ◽  
Patrick G. Gallagher ◽  
Lisa J. Garrett ◽  
George Stamatoyannopoulos ◽  
...  

ABSTRACT During development, changes occur in both the sites of erythropoiesis and the globin genes expressed at each developmental stage. Previous work has shown that high-level expression of human β-like globin genes in transgenic mice requires the presence of the locus control region (LCR). Models of hemoglobin switching propose that the LCR and/or stage-specific elements interact with globin gene sequences to activate specific genes in erythroid cells. To test these models, we generated transgenic mice which contain the human Aγ-globin gene linked to a 576-bp fragment containing the human β-spectrin promoter. In these mice, the β-spectrin Aγ-globin (βsp/Aγ) transgene was expressed at high levels in erythroid cells throughout development. Transgenic mice containing a 40-kb cosmid construct with the micro-LCR, βsp/Aγ-, ψβ-, δ-, and β-globin genes showed no developmental switching and expressed both human γ- and β-globin mRNAs in erythroid cells throughout development. Mice containing control cosmids with the Aγ-globin gene promoter showed developmental switching and expressed Aγ-globin mRNA in yolk sac and fetal liver erythroid cells and β-globin mRNA in fetal liver and adult erythroid cells. Our results suggest that replacement of the γ-globin promoter with the β-spectrin promoter allows the expression of the β-globin gene. We conclude that the γ-globin promoter is necessary and sufficient to suppress the expression of the β-globin gene in yolk sac erythroid cells.


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