Cross-linked double-stranded RNA from a defective vesicular stomatitis virus particle

A class of vesicular stomatitis defective interfering virus particles isolated in this laboratory contains mostly double-stranded RNA of approximately 0.7–0.9 × 10⁶ daltons molecular weight. This RNA “snaps-back” or reanneals independently of concentration after heat denaturation but remains denatured if first nicked with ribonuclease. The nicked denatured products are about half the size of the double-stranded RNA and approximately half of them anneal to infectious virion single-stranded RNA. It is proposed that the complementary strands of this double-stranded RNA are cross-linked to each other, probably covalently. The structure can be viewed best as a hairpin or a closed circle base-paired along most of its length.