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羟基脲对人红白血病细胞株中珠蛋白基因表达和细胞分化的影响 总被引:3,自引:1,他引:3
人红白血病细胞株(HEL细胞)中珠蛋白基因表达具有自己的特点。即只表达胚胎型的γ-珠蛋白基因而不表达成人型的β-珠蛋白基因。羟基脲(Hydroxyurea)是一种抑制DNA合成的小分子有机化合物。它在临床上被用来治疗地中海贫血和镰刀型贫血。我们的实验结果表明:随羟基脲浓度增加HEL细胞的增殖速度减慢。用常规RT-PCR方法和定量PCR分析证明;用羟基脲诱导HEL细胞后,β-珠蛋白基因表达增加,α-珠蛋白基因表达减少,而γ-珠蛋白基因表达变化不明显。对参与珠蛋白表达的转录因子GATA-1和NF-E2的定量PCR分析发现:这两种转录因子的表达均增加3倍以上。因此,羟基脲可能通过某些信号传递途径促进β-珠蛋白基因表达,从而使HEL细胞趋向终末分化。 相似文献
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以往研究表明, 用羟基脲诱导人红白血病细胞(HELcell)后, 能促进成年型β珠蛋白基因表达, 使HEL细胞趋向终末分化。本文试图进一步揭示羟基脲诱导HEL细胞分化的分子机制。GMSA 与Western 印迹分析结果显示, 随着羟基脲诱导HEL 细胞时间延长, 细胞核内的GATA1 转录因子的含量增加, 它与β珠蛋白基因5'旁侧DNA 序列内一个正调控序列(PCR:- 223~- 194 bp) 以及人工合成的GATADNA 序列结合能力增加; 与此相反,细胞核内的GATA2 转录因子的含量下降, 它与GATADNA 序列结合能力也下降。此外, 还检测到在羟基脲诱导HEL细胞后, 核内与YY1 类似的一个转录因子含量也迅速下降。实验结果表明GATA2 可能在红系细胞早期分化中起重要作用, 而GATA1 则在红系细胞终末分化过程中起调控作用。推测类似YY1 的一个转录因子可能具有抑制HEL细胞趋向终末分化的功能 相似文献
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以往研究表明,用羟基脲诱导人红白血病细胞(HELcell)后,能促进成年型β-珠蛋白基因表达,使HEL细胞趋向终末分化,本文试图进一步揭示羟基脲诱导HEL细胞分化的分子机制,GMSA与Western印迹分析结果显示,随着羟基脲诱导HEL细胞时间延长,细胞核内的GATA-1转录因子的含量增加,它与β-珠蛋白基因5旁侧DNA序列内一个正调控序列(PCR:-223~-194bp)以及人工合成的GATA/ 相似文献
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IL—3对人红白血病细胞株珠蛋白基因表达的影响 总被引:2,自引:0,他引:2
运用RT-PCR等方法研究了白细胞介素-3(IL-3)对人类红白血病细胞株(K562细胞)内珠蛋白基因表达的影响,结果显示,K562细胞在诱导前,不能表达β-珠蛋白基因,用IL-350u/ml诱导K562细胞3d和5d后,可检测到β珠蛋白基因的转录产物,而α珠蛋白基因和γ-珠蛋白基因在诱导前后无明显变化,同时,用苯肼当色细胞的方法检测到:K562细胞在诱导前蓝染细胞数极少,IL-3诱导K562细胞 相似文献
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羟基脲(Hydroxyurea)对细胞周期与珠蛋白基因表达的影响(简报) 总被引:7,自引:1,他引:7
Although the hydroxyurea (HU) has been extensively studied, little is known of its molecular mechanism in controlling the expression of human globin gene and in modulating the progression of cell-cycle in K 562 cell. In the present study, the effect of hydroxyurea on proliferative kinetics of K 562 cells was examined by monitoring the number of cells during a period of 8 day's cell culture. Our results showed that there was a dose related decrease in cell growth when K562 cells were incubated with HU. Moreover, cell-cycle analysis demonstrated that HU had profound effect on cell-cycle distribution. In the case of the induced K 562 cells, there was an increased accumulation of cells in S phase and a decreased fraction of cells in G 1 and G 2 + M phase. Furthermore, HU could induce the expression of human beta-globin gene in the induced K 562 cells. Our results indicate that HU has a potential to inhibit the proliferation of K 562 cells and to stimulate the terminal differentiation of this cell. 相似文献
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已有许多证据表明羟基脲能增加镰状细胞贫血及β-地贫病人的胎儿型血红蛋白(HbF)的合成。最近,有人报道羟基脲也能使一些患有β-地贫病人的β-珠蛋白基因表达增加。K562细胞是人红白血病细胞株,它只能表达胚胎型(ε-)与胎儿型(γ-)珠蛋白基因,而不能表达成年型(β-)珠蛋白基因。因此,K562 相似文献
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本文应用流式细胞分选仪和电子显微镜研究了IL-3和羟基脲对人红白血病细胞株(K562细胞)凋亡的影响.结果显示IL-3和羟基脲分别诱导K562细胞,不能引起细胞凋亡;而IL-3和羟基脲协同诱导K562细胞,可以引起细胞凋亡.用流式细胞仪检测到IL-3和羟基脲协同诱导K562细胞后,DNA含量低于二倍体的细胞数达31.90%,并产生明显的凋亡小峰.同时,IL-3和羟基脲协同诱导K562细胞,可抑制细胞周期中的S期,阻止细胞从S期进入G2/M期,使细胞周期延长,对K562细胞的生长和增殖具有抑制作用.在电镜下可观察到IL-3和羟基脲协同诱导的K562细胞,出现典型的凋亡细胞形态,细胞核内染色质浓缩、凝聚,紧靠在核膜边沿,形成新月形或环状的染色质结构,产生凋亡小体.提示IL-3和羟基脲具有协同效应,IL-3可提高K562细胞对羟基脲的敏感性,并可协同羟基脲诱导K562细胞凋亡. 相似文献
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本文主要以病毒感染的小鼠红白血病细胞为模型,使用显微分光光度术,利用荧光染料FITC以及PI,同时测量了在5mmol/L HMBA诱导MELC分化过程中不同周期时相单细胞内钙调素水平及DNA含量,结果表明,在MELC分化过程中细胞内钙调素水平在各周期时相均下降,这可能与MELC分化和细胞增殖受到抑制。G1期延延长有关。 相似文献
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羟基脲诱导前后HEL细胞内GATA转录因子与人β—类珠蛋白基因调控元件 … 总被引:1,自引:0,他引:1
HEL cells, a human erythroleukemia cell line, expressing mainly the gamma-globin genes, small amount of epsilon-globin gene, but not beta-globin gene. Our previous studies demonstrated that beta-globin gene could be expressed in HEL cells induced by hydroxyurea. However, the molecular mechenism is still unknown. Here the binding patterns of GATA factors (GATA-1 and GATA-2) to the regulatory elements of human beta-globin gene were examined with the nuclear extracts from hydroxyurea-induced and uninduced HEL cells. Our results showed in EMSA assay that GATA factors could bind to the core sequence of HS2(-10681 to -10971 bp), the 3' flanking sequence of HS2 core(-10323 to -10680 bp) and the promoter of human beta-globin gene(+20 to -112 bp). However, the binding patterns between hydroxyurea-induced and uninduced HEL cells were different. Furthermore, by using Western-blot analysis, our data showed that the amount of GATA-2 was decreased in hydroxyurea-induced HEL cells. In contrast to GATA-2, the amount of GATA-1 was increased in hydroxyurea-induced HEL cells. These results showed that the different members of GATA family might play different roles during the differentiation of erythrocytes. GATA-1 may stimulate the differentiation of HEL cells, while GATA-2 can probably inhibit the differentiation of HEL cells. 相似文献
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HEL细胞是一株人红白血病细胞株,其中成年型β-珠蛋白基因不能表达。我们以往的试验证明,羟基脲诱导以后,能使HEL细胞内成年型β-珠蛋白基因表达。本文以此为模型,探索了β-珠蛋白基因在HEL细胞内诱导表达的分子机制。结果表明,羟基脲诱导之后,与人β-珠蛋白基因5’远侧端DNaseⅠ超敏感点2核心DNA序列以及近侧端启动子DNA序列相结合的GATA-1蛋白因子量明显增多,而GATA-2蛋白因子量明显减少。结果显示,GATA蛋白家族各成员在HEL细胞分化及珠蛋白基因表达的过程中扮演着不同的角色。推测GATA-1可能有促进β-珠蛋白基因的表达,使HEL细胞趋向终末分化的作用,GATA-2则可能与胚胎型珠蛋白基因表达有关,并有抑制红细胞向终末分化的功能。 相似文献
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A Deisseroth R Velez R D Burk J Minna W F Anderson A Nienhuis 《Somatic cell genetics》1976,2(4):373-384
We have chosen human fibroblast x mouse erythroleukemia hybrid cells as a model system to examine regulation of unique genes. The globin genes were studied as a marker of erythroid differentiation. Three separate hybrid cell lines were incubated in 2% dimethylsulfoxide, an agent which induces erythroid differentiation of the parental erythroleukemia cells. Neither human nor mouse globin mRNA sequences could be detected by a sensitive molecular hybridization assay which utilized globin complementary D N A. However, td n a from one of the cell lines was shown to contain both the mouse and humand globin genes. Thus, loss of the genes by chromosomal segregation did not account for their failure to be expressed. Cocultivation of the mouse erythroleukemia cells with excess human fibroblasts did not prevent erythroid differentiation of the erythroleukemia cells in the presence of dimethylsulfoxide. Similarly globin gene expression was preserved in tetraploid cells generated by fusion of two erythroleukemia lines. Thus, extinction of globin geneated by fusion of two erythroleukemia lines. Thus, extinction of blobin gene expression in the human fibroblast x erythroleukemia hybrids occurred at the level of mRNA production and appeared to be due to the presence of the fibroblast genome within the hybrial cell. 相似文献
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Terminal differentiation of human erythroleukemia cell line K562 induced by aphidicolin 总被引:2,自引:0,他引:2
To analyze the relationship between differentiation and DNA replication, the effect of aphidicolin, a specific inhibitor for DNA polymerase alpha, was measured with respect to erythroid differentiation and activities of DNA polymerases alpha, beta, and gamma. Five micromolar aphidicolin completely blocked the growth of K562 cells and caused 80% of cells to become hemoglobin positive after 5 days exposure. The cessation of K562 cell growth induced by aphidicolin was irreversible, whereas the inhibition of HeLa cell growth was completely reversible. The enzyme activity of DNA polymerase alpha of K562 cells showed a 50-110% increase with aphidicolin treatment as compared to control K562 cells; activities of DNA polymerases beta and gamma were not affected. These features sharply contrasted with the erythroid induction of the same cells by hemin, where cell growth was not suppressed and DNA polymerase alpha was not increased but rather decreased. The enzyme activity of DNA polymerase alpha remained high even after removal of aphidicolin from the culture medium. These results suggest that treatment with aphidicolin might induce an accumulation of protein factors for replication and/or differentiation, causing rapid cell differentiation of cells without cell division. 相似文献
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To limit or stop cancer spreading, one of the most prevalent strategies is to induce cancer cell death. Differentiation therapy and apoptosis induction are two ways to achieve this goal. Sedimentation field-flow fractionation (SdFFF) has been described as an effective tool for cell separation, respecting integrity and viability. Because SdFFF takes advantage of intrinsic properties of eluted cells (size, density, shape), we studied the capacity of SdFFF to monitor specific biophysical modifications that occurred during cellular apoptosis or differentiation induction. Then, we used, as an in vitro cellular model of apoptosis and differentiation, diosgenin dose-dependent induction in the polyvalent human erythroleukemia cell line. Two other chemicals were used: phorbol myristate acetate (differentiation inducer) and staurosporine (apoptosis inducer). Our results demonstrated a correlation between SdFFF elution profile changes and induction of effective biological processes. Thus, after acquisition of a reference profile, SdFFF could be used alone to follow chemically induced biological events, suggesting many different applications such as testing series of molecules, evaluation of new cellular/biological models used in different life science fields, or sorting purified populations with the aim of better understanding mechanisms of induced cellular events. 相似文献
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Developmental regulation of fetal to adult globin gene switching in human fetal erythroid x mouse erythroleukemia cell hybrids 总被引:6,自引:0,他引:6
T Enver M Brice J Karlinsey G Stamatoyannopoulos T Papayannopoulou 《Developmental biology》1991,148(1):129-137
Human fetal erythroid x murine erythroleukemia cell hybrids undergo human fetal (gamma) to adult (beta) globin gene switching in vitro under the control of a mechanism located on human chromosome 11. We investigated whether this mechanism acts in cis or in trans by preparing hybrid cells containing marked fragments of the gamma and beta genes known to switch in transgenic mice. In these cells the chromosomally introduced human globin locus undergoes the fetal to adult globin gene switch. In contrast, the marked globin gene fragments were expressed at all stages of hybrid development. These results suggest that either the mechanism of switching acts in cis or that sequences present in the chromosomal globin locus but missing from the transfected globin gene fragments mediate its action. 相似文献
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