Cell proliferation is accompanied with changing levels of intracellular calmodulin (CaM) and its activation. Prior data from synchronized cell population could not actually stand for various CaM levels in different ph...Cell proliferation is accompanied with changing levels of intracellular calmodulin (CaM) and its activation. Prior data from synchronized cell population could not actually stand for various CaM levels in different phases of cell cycle. Here, based upon quantitative measurement of fluorescence in individual cells, a method was developed to investigate intracellular total CaM and Ca2+-activated CaM contents. Intensity of CaM immunoflurescence gave total CaM level, and Ca2+ -activated CaM was measured by fluorescence intensity of CaM antagonist trifluoperazine (TFP). In mouse erythroleuke-mia (MEL) cells, total CaM level increased from G1 through S to G2 M, reaching a maximum of 2-fold increase, then reduced to half amount after cell division. Meanwhile, Ca2+-activated CaM also in creased through the cell cycle (G1 , S, G2M). Increasing observed in G1 meant that the entry of cells from G1 into S phase may require CaM accumulation, and, equally or even more important, Ca2+-dependent activation of CaM. Ca2+- activated CaM decreased after cell divi-sion. The results suggested that CaM gene expression and Ca2+-modulated CaM activation act synergistically to accomplish the cell cycle progression.展开更多
Several drug-resistant variants have been developed by growing the parental MEL cells in presence of colchicine, adriamycin and vincristine respectively with stepwise increasing concentration. Both the colchicine-resi...Several drug-resistant variants have been developed by growing the parental MEL cells in presence of colchicine, adriamycin and vincristine respectively with stepwise increasing concentration. Both the colchicine-resistant Sc9(ColO) and vincristine-resis-tant Sc9(VCR5) cells displayed an accelerated HMBA-induced commitment to terminal cell differentiation, whereas the adriamycin-resistant SC9 (A 120) showed no acceleration but rather a substantial delay in HMBA-induced differentiation. The studies provide more clues as well as experimental models for further study on the mechanism of induced differentiation of MEL cells.展开更多
After injecting VP16, MEL cells and MEL-TF19 cells into the body of mice, with those injected with the same dose of saline as the control group, we observed the mice for their blood pictures, histological changes of t...After injecting VP16, MEL cells and MEL-TF19 cells into the body of mice, with those injected with the same dose of saline as the control group, we observed the mice for their blood pictures, histological changes of the liver and spleen, and the hemorhelogical indexes within 4 weeks. The results indicated that after injecting MEL cells, the mice entered into a pathological status similar to erythroleukemia, which had the following exhibitions: the tissue structures of the liver and spleen were damaged, a mass of proerythroblasts, basophil erythroblasts and polychromatophilic erythroblasts could be observed on the smears of the bone marrow and spleen, and the deformability and orientation ability of erythrocytes were both depressed. The pathogenicity of MEL-TF19 cells carrying TFAR19 gene was obviously lower than that of MEL cells, and the MEL-TF19 cells even lost their faintish pathogenicity under the apop-tosis-inducing effect of the chemotherapeutic reagent. The outcome from the animal experiments suggests that the TFAR19 gene suppresses the pathogenicity of MEL cells to the mice, and the effect may be better exerted with the synergy of the chemotherapeutic reagent.展开更多
A permanent lymphocyte cell line of a heterozygote with Yunnanese (Aγδβ)0-thalassemia deletion, associated with an increased production of Cry globin in adult, was founded using Epstein-Barr virus transformation. T...A permanent lymphocyte cell line of a heterozygote with Yunnanese (Aγδβ)0-thalassemia deletion, associated with an increased production of Cry globin in adult, was founded using Epstein-Barr virus transformation. The hybrids of the lymphocyte cell and mouse erythroleukemia cell (MEL) were achieved and the hybrids containing human chromosome 11 were selected with the monoclonal antibody 53/6. The subclones containing only either the normal or the abnormal human chromosome 11 were separated and the expression of the human globin genes was studied. Expression of the β-globin gene, but not the Cγ and Aγ, was observed in the hybrids containing only the normal human chromosome 11, while active expression of the Cγ globin gene was observed in the hybrids containing only the abnormal human chromosome 11. These results have confirmed that the DNA deletion in the β-globin gene cluster is the cause of persistent active expression of the Cγ globin gene in the Yunnanese mutant.展开更多
文摘Cell proliferation is accompanied with changing levels of intracellular calmodulin (CaM) and its activation. Prior data from synchronized cell population could not actually stand for various CaM levels in different phases of cell cycle. Here, based upon quantitative measurement of fluorescence in individual cells, a method was developed to investigate intracellular total CaM and Ca2+-activated CaM contents. Intensity of CaM immunoflurescence gave total CaM level, and Ca2+ -activated CaM was measured by fluorescence intensity of CaM antagonist trifluoperazine (TFP). In mouse erythroleuke-mia (MEL) cells, total CaM level increased from G1 through S to G2 M, reaching a maximum of 2-fold increase, then reduced to half amount after cell division. Meanwhile, Ca2+-activated CaM also in creased through the cell cycle (G1 , S, G2M). Increasing observed in G1 meant that the entry of cells from G1 into S phase may require CaM accumulation, and, equally or even more important, Ca2+-dependent activation of CaM. Ca2+- activated CaM decreased after cell divi-sion. The results suggested that CaM gene expression and Ca2+-modulated CaM activation act synergistically to accomplish the cell cycle progression.
文摘Several drug-resistant variants have been developed by growing the parental MEL cells in presence of colchicine, adriamycin and vincristine respectively with stepwise increasing concentration. Both the colchicine-resistant Sc9(ColO) and vincristine-resis-tant Sc9(VCR5) cells displayed an accelerated HMBA-induced commitment to terminal cell differentiation, whereas the adriamycin-resistant SC9 (A 120) showed no acceleration but rather a substantial delay in HMBA-induced differentiation. The studies provide more clues as well as experimental models for further study on the mechanism of induced differentiation of MEL cells.
基金the National Natural Science Foundation of China (Grant Nos. 30270355 & 10572007)
文摘After injecting VP16, MEL cells and MEL-TF19 cells into the body of mice, with those injected with the same dose of saline as the control group, we observed the mice for their blood pictures, histological changes of the liver and spleen, and the hemorhelogical indexes within 4 weeks. The results indicated that after injecting MEL cells, the mice entered into a pathological status similar to erythroleukemia, which had the following exhibitions: the tissue structures of the liver and spleen were damaged, a mass of proerythroblasts, basophil erythroblasts and polychromatophilic erythroblasts could be observed on the smears of the bone marrow and spleen, and the deformability and orientation ability of erythrocytes were both depressed. The pathogenicity of MEL-TF19 cells carrying TFAR19 gene was obviously lower than that of MEL cells, and the MEL-TF19 cells even lost their faintish pathogenicity under the apop-tosis-inducing effect of the chemotherapeutic reagent. The outcome from the animal experiments suggests that the TFAR19 gene suppresses the pathogenicity of MEL cells to the mice, and the effect may be better exerted with the synergy of the chemotherapeutic reagent.
基金Project supported by the National Natural Science Foundation of China.
文摘A permanent lymphocyte cell line of a heterozygote with Yunnanese (Aγδβ)0-thalassemia deletion, associated with an increased production of Cry globin in adult, was founded using Epstein-Barr virus transformation. The hybrids of the lymphocyte cell and mouse erythroleukemia cell (MEL) were achieved and the hybrids containing human chromosome 11 were selected with the monoclonal antibody 53/6. The subclones containing only either the normal or the abnormal human chromosome 11 were separated and the expression of the human globin genes was studied. Expression of the β-globin gene, but not the Cγ and Aγ, was observed in the hybrids containing only the normal human chromosome 11, while active expression of the Cγ globin gene was observed in the hybrids containing only the abnormal human chromosome 11. These results have confirmed that the DNA deletion in the β-globin gene cluster is the cause of persistent active expression of the Cγ globin gene in the Yunnanese mutant.
