The ability of (A,G)- and (G,T)-oligonucleotides to form triple-helice
s with a critical polypurine-polypyrimidine sequence of the c-Ki-ras p
romoter has been examined, together with their capacity to inhibit the
expression of the chloramphenicol acetyl-transferase gene driven by t
he c-Ki-ras promoter in a transfected cellular system.