[Study of the double-stranded fragments in the poly(A)-containing cytoplasmic RNA of the rat liver].

The double-stranded sequences in the poly(A)-containing cytoplasmic RNA (c-dsRNA) hybridize mainly with the repetitive DNA. 70-80% of double-stranded regions in the cytoplasmic poly (A)-RNA are identical to double-stranded regions of heterogeneous nuclear RNA in normal as well as in cortisone-treated rats. The thermal stability of cytoplasmic double-stranded regions is higher in the presence of polyadenylate sequences than in their absence. It is suggested that the double-stranded sequences in the poly (A) +RNA interact with poly (A) stretches and form higher order structures. The thermal stability of c-dsRNA isolated from cortisone-treated rats is higher than that from control rats.