Inhibition of Transcription of the Human c-myc Protooncogene by Intermolecular Triplex

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• 作者：Hyung-Gyoon Kim ; James F. Reddoch ; Charles Mayfield ; Scot Ebbinghaus ; Nadarajah Vigneswaran ; Sheila Thomas ; David E. Jones ; Jr. ; and Donald M. Miller
• 刊名：Biochemistry
• 出版年：1998
• 出版时间：February 24, 1998
• 年：1998
• 卷：37
• 期：8
• 页码：2299 - 2304
• 全文大小：181K
• 年卷期：v.37,no.8(February 24, 1998)
• ISSN：1520-4995

文摘

Triplex-forming oligonucleotides (TFOs) have been shownto inhibit both transcription in vitroand the expression of target genes in cell culture by binding topolypurine/polypyrimidine sequences inseveral human gene promoters. The c-myc protooncogeneis overexpressed in a variety of human cancersand appears to play an important role in the proliferation of thesecells. In an attempt to assay the abilityof triplex-forming oligonucleotides to inhibit expression of a targetgene in vivo, we have developed acellular system involving transfection of a c-mycpromoter-driven luciferase reporter plasmid with triplex-forming oligonucleotides targeted to the human c-mycprotooncogene. To increase the stability of theTFO, we have used modified phosphorothioate oligonucleotides.Triplex formation with a modifiedphosphorothioate oligonucleotide occurs with approximately equalbinding affinity as that seen using aphosphodiester oligonucleotide. Phosphorothioate-modified TFOstargeted to c-myc inhibit transcriptionof the c-myc promoter in HeLa cells as demonstrated by adecrease in luciferase expression from a luciferasereporter gene construct. These results suggests that triplexformation may represent a gene-specific meansof inhibiting specific protooncogene expression.