The Structure and Replication of Coronaviruses

Abstract

Coronaviruses were recognized as a group in 1968 primarily on the basis oftheir characteristic morphology as seen in the electron microscope (Tyrrell et al. 1968). Since that time our knowledge of the structure and replication of these viruses has increased steadily and has been periodically reviewed (Mdntosh 1974; Tyrrell et al. 1978; Robb and Bond 1979a). The basis for this review, which concentrates on the molecular biology of coronaviruses, is principally the new data which has become available in the last 2 years. The pathogenicity of these viruses, which are associated with many diseases of clinical importance in animals and humans, is the subject of the accompanying article. Coronaviruses infect a wide variety of animal species ranging from fowl to humans. The group comprises 11 recognized viruses, and five more that are tentatively included

Coronavirus JHM: Coding Assignments of Subgenomic mRNAs

“…Thus, the gene order for MHV-JHM can be deduced as 5'-NSA-NSB(30K)--gp170/gp98-NSD/NSE(14K)-p23/gp25-pp60-3'. [The nomenclature used here follows that given in Siddell et al (1982), where NSA, NSB, etc represent non-structural polypeptides A, B, etc. ] A number of comments on the MHV-JHM replication strategy can be made.…”

Synthesis and Processing of the Bovine Enteric Coronavirus Haemagglutinin Protein

“…This is presumably the site of budding for the closely related BCV and other coronaviruses that have been shown to bud into intracytoplasmic vesicles (Mebus et al, 1973;Siddell et al, 1982). It has also been documented for the peplomer (E2) protein of mouse hepatitis virus that initial N-linked glycosylation is a cotranslational or very early (pre-Golgi) event, and that processing of the carbohydrate chains to complex forms by Golgi enzymes (Kornfeld & Kornfeld, 1985) occurs on proteins of assembled virions as the virions progress through the Golgi on a secretory pathway to the cell surface (Repp et al, 1985).…”

“…Coronaviruses have been generally described as possessing three structural proteins: a phosphorylated nucleocapsid protein (N) of 50K to 60K, a glycosylated matrix-like protein (M or El) of 23K to 29K, and a glycosylated peplomeric protein (P or E2) of 150K to 200K, that in many cases is proteolytically cleaved into two subunits of roughly equal size (for review, see Siddell et al, 1982). Recently, a fourth structural protein has been described as a part of the mammalian coronaviruses that haemagglutinate.…”

Intracellular RNAs of the Feline Infectious Peritonitis Coronavirus Strain 79-1146

“…Coronavirions contain three main structural proteins : a glycosylated peplomer protein (E2), a transmembrane envelope glycoprotein (El) and a phosphorylated nucleocapsid protein (N). The coronavirus genome is a positive-stranded RNA of at least 20 kb (for reviews, see Siddell et al, 1982;Sturman & Holmes, 1983). During replication a negative strand serves as a template for the synthesis of one genome-sized and multiple subgenomic mRNAs (Lai et al, 1982;Spaan et al, 1981 ;Stern & Kennedy, 1980).…”

“…The viral mRNAs have a nested set structure with 3' coterminal ends and sequences extending different lengths in the 5' direction. Of each RNA, only the unique 5' terminal sequences, not present in the next smaller RNA of the set, are translated (Siddell et al, 1982;Sturman & Holmes, 1983). A characteristic feature of coronavirus mRNAs is the presence of a short 5' common 'leader' sequence.…”