Coronavirus multiplication strategy. II. Mapping the avian infectious bronchitis virus intracellular RNA species to the genome

Abstract

Avian infectious bronchitis virus, a coronavirus, directs the synthesis of 6 major single-stranded polyadenylated RNA species in infected chicken embryo kidney cells. These RNA include the intracellular form of the genome (RNA F) and 5 smaller RNA species (RNA A, B, C, D and E). Species A, B, C and D are subgenomic RNA and together with the genome form a nested sequence set, with the sequences of each RNA contained within every larger RNA species. RNase T1 oligonucleotide fingerprinting showed that RNA E is also a member of the nested set. Partial alkaline fragmentation of the genome followed by sucrose fractionation, oligodeoxythymidylate-cellulose chromatography and RNase T1 fingerprinting gave a partial 3''-to-5'' oligonucleotide spot order. A comparison of the oligonucleotides of each of the 5 subgenomic RNA with this spot order established that all of the RNA are comprised of nucleotide sequences inward from the 3'' end of the genome. This result is discussed in relation to the multiplication strategy both of coronaviruses and of other RNA-containing viruses.