Newcastle disease virus RNA: II. Preferential synthesis of RNA complementary to parental viral RNA by chick embryo cells

Abstract

Following infection by strain “C” of Newcastle disease virus, and during incubation in the presence of actinomycin D, chick embryo cells synthesized RNA which had a base composition complementary to the base composition of RNA from virus particles. Evidence for base-sequence complementarity between RNA from virus particles and RNA synthesized by infected cells was obtained by in vitro hybridization. Of the total radioisotopically labeled RNA synthesized by infected cells in the presence of actinomycin D, 80% or more became insensitive to pancreatic ribo-nuclease after annealing with RNA from virus particles. The ribonuclease-resistant RNA had properties of a double-stranded polynucleotide. RNA from chick embryo cells or from Escherichia coli cells did not render labeled RNA from Newcastle disease virus-infected cells resistant to ribonuclease, and RNA from virus particles did not confer ribonuclease resistance on RNA from uninfected chick embryo cells. From 18 to 40% of the labeled RNA obtained from infected cells became RNase-resistant when annealed in the absence of RNA from virus particles. Cells infected by any of four other strains of Newcastle disease virus synthesized RNA, which was complementary in base composition to RNA from strain “C” virus particles. Virus particle RNA from all of these strains hybridized with RNA from cells infected by the “C” strain.