Genome of infectious bronchitis virus

Abstract

Techniques are described for the growth and rapid purification of the avian coronavirus infectious bronchitis virus (IBV). Purified IBV has a sedimentation coefficient of 320S and a buoyant density of 1.22 g/ml in sucrose-deuterium oxide equilibrium gradients. IBV RNA extracted by proteinase K in the presence of sodium dodecyl sulfate and further purified by phenol extraction and gradient centrifugation is single stranded and has a sedimentation coefficient of 64S, as determined by isokinetic gradient centrifugation. Analysis on sucrose gradients under both aqueous and denaturing conditions together with agarose gel electrophoresis in the presence of the chaotropic agent methylmercuric hydroxide gave a value of 8 x 106 for the molecular weight of IBV RNA. This value was

The coronavirus avian infectious bronchitis virus requires the cell nucleus and host transcriptional factors

“…RNA polymerase II as a multicomponent enzyme which exists in at least three structurally distinct forms has been directly implicated in the synthesis of viral mRNAs (or their precursors) of various DNA viruses and RNA retroviruses (Roeder, 1976). While the avian coronaviruses are credited with possessing the largest single-stranded RNA genome (Lomniczi and Kennedy, 1977), the manner in which it is replicated is presently unknown (Robb and Bond, 1979). One possibility is that IBV and other positive-stranded coronaviruses utilize a virus-coded RNA-dependent RNA polymerase which is a hybrid enzyme containing one or more host components including specific subunits derived from nuclear RNA polymerase II.…”

“…Various members of the coronavirus group have recently been shown to contain single-stranded RNA genomes of positive messenger polarity (Schochetman, et al, 1977;Lomniczi and Kennedy, 1977;Lai and Stohlman, 1978). Since it has not been firmly established whether the replication of the prototype coronavirus, avian infectious bronchitis virus (IBV), is restricted to cytoplasmic sites and whether productive infections with this ribovirus are regulated, in part, by unidentified host factors (McIntosh, 1974;Tyrrell et al, 1978), we undertook the present investigation of IBV biogenesis utilizing inhibitors which compromise normal function of the host cell transcriptional apparatus.…”

The Molecular Biology of Coronaviruses

“…The genomes of coronaviruses are nonsegmented, single-stranded RNA molecules of positive sense, that is, the same sense as mRNA ( Fig. 4) (Lai and Stohlman, 1978;Lomniczi and Kennedy, 1977;Schochetman et al, 1977;Wege et al, 1978). Structurally they resemble most eukaryotic mRNAs, in having both 5 0 caps (Lai and Stohlman, 1981) and 3 0 poly(A) tails (Lai and Stohlman, 1978;Lomniczi, 1977;Schochetman et al, 1977;Wege et al, 1978).…”

Pathogenic murine coronaviruses I. Characterization of biological behavior in vitro and virus-specific intracellular RNA of strongly neurotropic JHMV and weakly neurotropic A59V viruses

“…The viron RNA of avian infectious bronchitis virus, an avian coronavirus, contains at least one tract of polyadenylic acid and is infectious (Schochetman et al, 1977, Lomniczi, 1977. Furthermore, this avian virion RNA is the largest single-stranded RNA genome yet described in animal virology and is of messenger polarity (Lomniczi and Kennedy, 1977).…”