title: Polyadenylic-polyxanthylic-polyuridylic acid triple helix.
abstract: Poly(xanthylic acid) [X)n] abolished the ability of (A)n-(U)n to induce interferon in "superinduced" (actinomycin D and cycloheximide) primary rabbit kidney cells. Under the same conditions, (X)n had a relatively minor effect on the interferon inducing capacity of (I)n-(C)n. Evidence based on mixing curves, melting profiles, pancreatic ribonuclease resistance and sucrose gradient ultracentrifugation pointed to the conclusion that the following three reactions occur depending on stoichiometry: (1) 2(A)n-(U)n + (X)n leads to (A)n-2(U)n + (A)n-(X)n; (2) (A)n-(U)n + (X)n leads to (A)n-(U)n-(X)n; (3) (A)n-(U)n + 2(X)n + (X)n-(U)n. The second reaction represents the formation of a new triple helix which can also be formed according to the following reactions: (X)n-(U)n + (A)n leads to (A)n-(X)n-(U)n; (A)n-(X)n + (U)n leads to (A)n-(X)n-(U)n.
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D007372:Interferons / Q000096:biosynthesis; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009693:Nucleic Acid Hybridization; D011061:Poly A; D011063:Poly A-U / Q000037:antagonists & inhibitors; D011072:Poly U; D011131:Polyribonucleotides / Q000494:pharmacology; D013696:Temperature; D014970:Xanthines
chemical_list: D011131:Polyribonucleotides; D014970:Xanthines; D011063:Poly A-U; D011061:Poly A; D011072:Poly U; D007372:Interferons