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60Co-γ辐照对中国仓鼠卵巢成纤维细胞DNA和组蛋白合成的影响
THE EFFECT OF 60CO-IRRADIATION ON SYNTHESIS OF DNA AND HISTONE IN CHINESE HAMSTER OVARY FIBRILBLAST CELLS
【摘要】 本文介绍了60Co-γ辐照对同步的和非同步的CHO细胞的DNA合成和组蛋白合成关系的影响的研究,用3H-胸腺嘧啶核苷和14C-丙氨酸双标记,未经辐照的和经4Gy~60Gy 60Co-γ辐照的CHO细胞,通过3H和14C的参入来估价DNA和组蛋白的合成,并用聚丙烯酰胺凝胶电泳鉴定辐照前后组蛋白各组分的变化情况,实验表明: 1)、在4~60Gy剂量范内,无论是同步的还是非同步的CHO细胞其DNA合成和组蛋白合成都受到不同程度的抑制。2)、在辐照后1—3小时,DNA合成和组蛋白合成都受到不同程度的抑制,但辐照后4小时,DNA合成被进一步抑制而组蛋白的合成却逐渐恢复正常,到辐照后48小时组蛋白的合成几乎接近对照水平。3)、16Gy 60Co-γ辐照后8小时,非同步的CHO细胞的DNA合成被抑制的情况比G1期CHO细胞更为严重。4)、16Gy 60Co-γ辐照S期细胞,在辐照后1—24小时中DNA合成被明显抑制的同时,组蛋白的合成也受到相应的抑制。5)、从未经辐照的和经6、16和60Gy60Co-γ辐照的CHO细胞分别提取全组蛋白,进行聚丙烯酰胺凝胶电泳,从电泳图谱的变化清楚地看到组蛋白H1和H3受辐照影响大于组蛋白H4和H2B+H2A,因此我们推测DNA合成和组蛋白H1和H3的关系较之组蛋白H4和H2A+H2B更为密切。
【Abstract】 The relationship between histonesynthesis and DNA synthesis in asynchronized and S phase synchronizedCHO cells following γ-irradiation wasinvestigated.Radiation dose was 4——60Gy with dose rate of 0.78 Gy/min.The DNA and histone content ofboth irradiated and unirradiated cellsdoubly labelled with 3H-thymidine and14C-alanine were determined and thepolyacrylamide gel electrophoresis method was used to display the radiationinduced changes in histone composi-tion.The results have shown: 1) The DNA and histone syn-thesis were inhibited to some extent inboth asynchronized and S phase syn-chronized cells following irradiation,degree of inhibition being increasedwith irradiation dose. 2) The incorporation of 3H-thy-midine and 14C-alanine into CHOcells was significantly inhibited in thefirst 3 hours after irradiation of 16Gy,from the 4th hour the incorporationrate of 14G-alanine began to recoverand almost backed to normal at the48th hour after irradiation,but theincorporation of 3H-thymidine wasstill depressed during this period. 3) The rate of DNA synthesis inasynchronous cells was more seriouslydepressed than that in synchronouscells of G1 stage at the 8th hour afterirradiation. 4) The histone was extractedfrom both irradiated and controlledcells by 0.25 N HCL,and then frac-tionted by polyacrylamide gel elec-trophoresis.It was shown that after irradiation H1 and H3 histonebands were markedly deminished.Itis supposed that there may exists certain coupling between DNA synthesis and the synthesis of H1 and H2histone.
【Key words】 60Co-irradiation.DNA; systhesis.Histone; synthesis.CHO; fibrilblast; cell.;
- 【文献出处】 实验生物学报 ,Acta Biologiae Experimentalis Sinica , 编辑部邮箱 ,1984年01期
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