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
Objective. To investigate the roles of mouse erythroid differentiation and denucleation factor (MKI)DF), a novel factor cloned in our laboratory recently, in erylhroid terminal differentiation.Method. Mouse erythroleu...Objective. To investigate the roles of mouse erythroid differentiation and denucleation factor (MKI)DF), a novel factor cloned in our laboratory recently, in erylhroid terminal differentiation.Method. Mouse erythroleukemia (MEL) cells were transfected with eukaryotie expression plasinid pcl)-NA-MEDDF. Then we investigated the changes on characteristics of cell growth by analyzing cells growth rate, mitotie index and colony-forming rate in semi-solid medium. The expressions of c-mye and p-globin genes were analysed by semi-quantitative RT-PCR.Results. MEL cells transfected with pcDNA-MEDDF showed significant lower growth rate, mitolic index,and colony-forming rate in semi-solid medium ( P<0. 01). The percentage of benzidine-positive cells was 32. 8%after transfection. The expression of β-globin in cells trarisfected with pcDNA-MEDDF was 3. 43 times higherthan that of control (MEL transfected with blank vector, pcDNA3. 1), and the expression of c-rnyc decreased by66. 3% .Conclusions. MEDDF can induce differentiation of MEL cell and suppress its malignancy.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.
基金This work supported by the National Natural Sciences Foundation of China(39670364)This work was originally published in Acta Academiae Medicinae Sinicae(200123: 32-35)in Chinese.
文摘Objective. To investigate the roles of mouse erythroid differentiation and denucleation factor (MKI)DF), a novel factor cloned in our laboratory recently, in erylhroid terminal differentiation.Method. Mouse erythroleukemia (MEL) cells were transfected with eukaryotie expression plasinid pcl)-NA-MEDDF. Then we investigated the changes on characteristics of cell growth by analyzing cells growth rate, mitotie index and colony-forming rate in semi-solid medium. The expressions of c-mye and p-globin genes were analysed by semi-quantitative RT-PCR.Results. MEL cells transfected with pcDNA-MEDDF showed significant lower growth rate, mitolic index,and colony-forming rate in semi-solid medium ( P<0. 01). The percentage of benzidine-positive cells was 32. 8%after transfection. The expression of β-globin in cells trarisfected with pcDNA-MEDDF was 3. 43 times higherthan that of control (MEL transfected with blank vector, pcDNA3. 1), and the expression of c-rnyc decreased by66. 3% .Conclusions. MEDDF can induce differentiation of MEL cell and suppress its malignancy.
