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Triple helix formation at A 8 XA 8 ·T 8 YT 8

1993; Wiley; Volume: 332; Issue: 1-2 Linguagem: Inglês

10.1016/0014-5793(93)80510-2

1873-3468

Simon Chandler, Keith R. Fox,

RNA modifications and cancer

We have examined the formation of DNA triple helices between the oligonucleotides T 8 XT 8 (X = A,C,G,T) and DNA fragments containing the target sequences A 8 XA 8 · T 8 YT 8 (X = T,C,G; Y=A,G,C), by DNase I footprinting. We find that A 8 GAg 8 · T 8 CT 8 yields a footprint with T 8 CT 8 and shows a weaker interaction with T 17 and T 8 GT 8 · A 8 CA 8 · T 8 GT 8 yields a footprint with T 17 , and shows weaker interaction with T 8 CT 8 . A 8 TA 8 · T 8 AT 8 yields a footprint with T 8 GT 8 and shows weaker interaction with T 17. Each of the successful complexes is characterised by enhanced DNase I cleavage at the 3' end of the purine strand of the target, as well as protection at the 5' end. We have been unable to form triplexes with third strands of the type A 8 XA 8 .