The nucleic acid of infectious bronchitis virus

Abstract

SummaryThe nucleic acid of infectious bronchitis virus (IBV), like that of other enveloped viruses, consists of discontinuous single stranded RNA. However, unlike many other viruses, there is extreme heterogeneity in the sizes of the I~NA fragments, as revealed by centrifugation in sucrose gradients or electrophoresis in polyacrylamide gels. Two principal classes of I~NA fragments are present: ~) A larger class comprising 74.9--85.4 per cent of total RNA and consisting of fragments having molecular weights ranging from 0.5 • 106 to considerably greater than 3.0 • 106 da]tons and, b) A smaller class comprising 9.1--19.7 per cent of total I~NA with the size approximately that of ribosomal r S I~NA.All IBV RNA's were fully susceptible to ribonuclease and had a buoyant density in caesium sulphate identical to that of tobacco mosaic virus RNA. :No difference in the R:NA profile for IBV was observed from the use of different methods of virus purification. The single-stranded R:NA's of poliovirus and tobacco mosaic virus remained undegraded after preparation in the presence of IBV.

The characterisation of the virion RNA of avian Infectious Bronchitis Virus

“…Previous reports have shown that the nucleic acid of IBV is RNA [4,5] although there is some discrepancy as to the size of this RNA. Tannock [4] analysed phenol-extracted IBV RNA and showed it to consist of extremely heterogeneous RNA fragments, while Watkins et al [S] have shown that the IBVgenome extracted with 1% SDS at 60°C is a single large mol.…”

“…Tannock [4] analysed phenol-extracted IBV RNA and showed it to consist of extremely heterogeneous RNA fragments, while Watkins et al [S] have shown that the IBVgenome extracted with 1% SDS at 60°C is a single large mol. wt (9.0 X 106) RNA species.…”

Isolation and Morphology of the Internal Component of Human Coronavirus, Strain 229E

“…Direct confirmation of the RNA content of infectious bronchitis virus (IBV) has now been provided by T ann ock [17] and W a tk ins et al [18] and of HCV by J.C. H ierh o lzer (reported by T yrrell et al [8]). However, at tempts to resolve the structure of the internal component of the se viruses have, until now, proven unsuccessful.…”

The RNA of human coronavirus OC-43

“…Phenol (Fisher, reagent grade) for RNA extraction was twice distilled. Yeast carrier RNA was prepared according to the method of Tannock (1973 Virus was released from cells in the suspension by freezing and thawing four times, and particulate matter was removed by centrifuging at 5,000 g in a Spinco 40 rotor for 20 min. The supernatant was retained in an ice bath while the pellet was resuspended in PBS to 20% of the original volume and recentrifuged; both supernatants were then combined for purification.…”

“…The Coronaviridae were described as a separate taxonomic group by Almeida et al (1968) but, despite their ubiquity and economic importance, few biophysical characterization studies have been reported. The RNA of avian infectious bronchitis virus (IBV) was first described by Tannock (1973), who obtained from purified virions a highly heterogeneous array of RNA fragments using a phenol-sodium dodecyl sulfate (SDS) extraction procedure. Fragments ranged in molecular weight from 0.5 x lo6 to more than 3.0 x 106; a smaller, more homogeneous class of a size similar to ribosomal 4 S RNA was also present.…”