The Molecular Biology of Coronaviruses

SUMMARYInfection of rat cells, Schwannoma RN2, hepatoma HTC or myoblast L6, with the murine coronavirus JHM strain results in a persistent infection characterized by the release of virus over an extended period of time with a limited cytopathology. Several stages of the viral replication cycle have been examined in these cells in comparison to those in mouse L2 cells, which are totally permissive to JHM infection. Although the rat cells bound as much virus as the mouse cells their ability to internalize it was 40-fold less efficient than the mouse cells. This lower internalization efficiency was not enhanced by pH shock of infected cells, but was by treatment with polyethylene glycol. In all cell types there appeared to be no major differences in the ability of the internalized virus to replicate the viral RNA as determined by slot-blot analysis with a radiolabelled viral cDNA. A similar genetic mechanism appears to be operative in the lines because somatic cell hybrids formed between these lines in various combinations were also deficient in the ability to internalize bound virus. Taken together these results imply that rat cell lines in general share a common deficiency in their inability to internalize murine coronaviruses efficiently. This low efficiency in viral internalization may explain in part the ability of these lines to sustain persistent infections.

Section: Discussionmentioning

confidence: 99%

Section: Peg-induced Cell Fusionmentioning

confidence: 99%

Section: Adsorptionmentioning

confidence: 99%

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Several Rat Cell Lines Share a Common Defect in Their Inability to Internalize Murine Coronaviruses Efficiently

Flintoff¹,

Dinter²

1989

“…The Coronaviridae family contains four antigenic groups (Pederson et al, 1978;Sturman & Holmes, 1983). Viruses within each group possess partial antigenic cross-reactivities and infect a variety of mammalian and avian species .…”

Section: Introductionmentioning

confidence: 99%

Sequence analysis of the turkey enteric coronavirus nucleocapsid and membrane protein genes: a close genomic relationship with bovine coronavirus

Verbeek¹,

Tijssen²

1991

The 3' end of the turkey coronavirus (TCV) genome and the gene encoding the nucleocapsid protein (N) were cloned and sequenced. The gene encoding the membrane protein (M) was obtained by cloning a polymerase chain reaction (PCR)-amplified fragment obtained using bovine coronavirus (BCV)-specific primers. Furthermore, five TCV DNA fragments, obtained by PCR on RNA from clinical specimens and corresponding to either the N terminus of the M protein or the complete M protein were also cloned and sequenced. The sequence revealed a 3' non-coding region of 291 bases, an open reading frame (ORF) encoding the N protein with a predicted size of 448 amino acids, or an Mr of 49K, and an ORF encoding the M protein with a predicted size of 230 amino acids and an Mr of 26K. A third ORF, encoding a hypothetical protein of 207 amino acids with an Mr of 23K was found within the N gene sequence. The amino acid sequences of both the N and M proteins were more than 99% similar to those published for BCV. Extensive similarity was also observed between the amino acid sequences of the TCV N protein and those of murine hepatitis virus (MHV) (70%) and human respiratory coronavirus strain OC43 (HCV-OC43) (98%) and between the amino acid sequences of the predicted M proteins of TCV and MHV (86 %). Such striking identity suggests that BCV, TCV and HCV-OC43 must have diverged from each other only recently. A potential N-glycosylation site was found at the N terminus of the TCV M protein and is situated at the same location in BCV, MHV and transmissible gastroenteritis virus.

“…The causative virus (FIPV) is a member of the family Coronaviridae, a group of enveloped RNA viruses with a single-stranded, positivesense genome (for reviews, see Siddell et al, 1983;Sturman & Holmes, 1983). The pathogenesis of FIP is thought to be the result of complex immunologically mediated phenomena (Horzinek & Osterhaus, 1979).…”

Section: Introductionmentioning

confidence: 99%

cDNA Cloning and Sequence Analysis of the Gene Encoding the Peplomer Protein of Feline Infectious Peritonitis Virus

Groot

Maduro

Lenstra

et al. 1987

SUMMARYThe peplomer gene of feline infectious peritonitis virus (FIPV) strain 79-1146 was isolated from a genomic cDNA library by differential hybridization with RNA 2 and 3 as probes. From the nucleotide sequence a primary translation product of 1452 residues (Mr 160472) was predicted, containing an N-terminal signal sequence, a C-terminal transmembrane segment and 35 potential N-linked glycosylation.sites. By S1 nuclease analysis the 5' end of the presumptive RNA 2 body was located at about 30 nucleotides upstream from the initiating AUG codon. At approximately the same position a nine nucleotide sequence ACUAAACUU was found, which was also present 37 nucleotides downstream from the open reading frame. Comparison of the sequences of the FIPV, murine hepatitis virus and infectious bronchitis virus peplomer proteins showed about 27% overall homology, with most conservation in the C-terminal half.