Hu Xiao-wen, Huang Hong-zhang, Yu Dong-sheng
Dept. of Oral and Maxillofacial Surgery, The Second Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510120, China.
Hua Xi Kou Qiang Yi Xue Za Zhi. 2007 Aug;25(4):399-403.
To study the effects of adramycin to disturb telomeric extention reaction mediated by telomerase of Tca8113 cells by inducing oligonucleotides that contain telomeric repeats to form guanine-quadruplex (G4) structures.
In the presence of adriamycin, d(TTAGGG)4, d(TTAGAG)4, d(TTAGGG)5 and d(TTAGGGT) were analyzed by electrophoretic mobility shift assay. The mobility of d(TTAGGG)3, d(TTAGGG)4 and d(TrAGGG)5 in native polyacrylamide electrophoresis were observed. Methylation protection experiments were performed to investigate the effects of adriamycin on methylation of guanine in d(TTAGGG)4 and d(TTAGAG)4. The traditional telomeric repeats amplification protocol (TRAP) and modified TRAP-G4 assays were, respectively, used to analyze the different characteristcs of adriamycin's inhibiting telomeric extension mediated by telomerase of Tca8113 cells.
At 5.00 microg/mL of adriamycin, conversion of some of linear d(TrAGGG)4 and d(TrAGGG)5to the new, high-mobility bands formed by complex with special second structures were found in the mobility shift assay. Adriamycin at 1.25 microg/mL protected the G in d(TIAGGG)4 from methylating. Adriamycin at 2.50 microg/mL or 1.25 microg/mL partially inhibited the telomeric extension lengthened by telomerase of Tca8113 cells in TRAP assay, but completely did so in TRAP-G4 assay.
Adriamycin is able to disturb telomeric extention mediated by telomerase of Tca8113 cells by inducing oligonucleotides that contain telomeric repeats to form intra-molecular G4 structures.
通过诱导含有端粒重复序列的寡核苷酸形成鸟嘌呤四链体（G4）结构，研究阿霉素对Tca8113细胞端粒酶介导的端粒延伸反应的影响。
在阿霉素存在的情况下，通过电泳迁移率变动分析对d(TTAGGG)4、d(TTAGAG)4、d(TTAGGG)5和d(TTAGGGT)进行分析。观察d(TTAGGG)3、d(TTAGGG)4和d(TrAGGG)5在非变性聚丙烯酰胺凝胶电泳中的迁移情况。进行甲基化保护实验以研究阿霉素对d(TTAGGG)4和d(TTAGAG)4中鸟嘌呤甲基化的影响。分别采用传统的端粒重复序列扩增法（TRAP）和改良的TRAP-G4法分析阿霉素抑制Tca8113细胞端粒酶介导的端粒延伸的不同特性。
在电泳迁移率变动分析中，当阿霉素浓度为5.00μg/mL时，发现一些线性的d(TrAGGG)4和d(TrAGGG)5转变为与特殊二级结构形成复合物的新的高迁移率条带。1.25μg/mL的阿霉素可保护d(TIAGGG)4中的鸟嘌呤不被甲基化。在TRAP实验中，2.50μg/mL或1.25μg/mL的阿霉素可部分抑制Tca8113细胞端粒酶延长的端粒延伸，但在TRAP-G4实验中则完全抑制。
阿霉素能够通过诱导含有端粒重复序列的寡核苷酸形成分子内G4结构来干扰Tca8113细胞端粒酶介导的端粒延伸。
