The structure and functions of coronavirus genomic 3′ and 5′ ends

Abstract

Coronaviruses (CoVs) are an important cause of illness in humans and animals. Most human coronaviruses commonly cause relatively mild respiratory illnesses; however two zoonotic coronaviruses, SARS-CoV and MERS-CoV, can cause severe illness and death. Investigations over the past thirty-five years have illuminated many aspects of coronavirus replication. The focus of this review is the functional analysis of conserved RNA secondary structures in the 5’ and 3’ of the betacoronavirus genomes. The 5’ 350 nucleotides folds into a set of RNA secondary structures which are well conserved, and reverse genetic studies indicate that these structures play an important role in the discontinuous synthesis of subgenomic RNAs in the betacoronaviruses. These cis-acting elements extend 3’ of the 5’UTR into ORF1a. The 3’UTR is similarly conserved and contains all of the cis-acting sequences necessary for viral replication. Two competing conformations near the 5’ end of the 3’UTR have been shown to make up a potential molecular switch. There is some evidence that an association between the 3’ and 5’UTRs is necessary for subgenomic RNA synthesis, but the basis for this association is not yet clear. A number of host RNA proteins have been shown to bind to the 5’ and 3’ cis-acting regions, but the significance of these in viral replication is not clear. Two viral proteins have been identified as binding to the 5’ cis-acting region, nsp1 and N protein. A genetic interaction between nsp8 and nsp9 and the region of the 3’UTR that contains the putative molecular switch suggests that these two proteins bind to this region.

Sero-prevalence, cross-species infection and serological determinants of prevalence of Bovine Coronavirus in Cattle, Sheep and Goats in Ghana

“…BCoV is an enveloped plus strand RNA virus that belongs to the https://doi.org/10. 1016 T genus Betacoronavirus (Yang and Leibowitz, 2015;Oma et al, 2016;Pfefferle et al, 2009). While different strains may have some antigenic variability, all strains elicit cross-reactive seropositivity and thus form a single serotype (Clark, 1993;El-Ghorr et al, 1989).…”

Nidovirus RNA polymerases: Complex enzymes handling exceptional RNA genomes

“…The importance of multiple of these elements is supported by bioinformatics (conservation), biochemical probing, and site-directed mutagenesis. For an overview of the structure and function of the RNA elements that have been implicated in CoV or AV replication and transcription, the reader is referred to detailed reviews that have been published elsewhere (Madhugiri et al, 2016;Masters, 2007;Sola et al, 2011;Yang and Leibowitz, 2015). However, it has remained largely unclear whether these elements interact with the RdRp domain-containing subunit directly or with other components of the RTC, as for example reported by Züst et al who observed that second-site mutations in the small nsp8 and nsp9 subunits of the RTC could compensate for mutations in conserved RNA sequences near the genomic 3 end of the murine hepatitis coronavirus (MHV) genome (Züst et al, 2008).…”

Coronavirus Pnömoenteritis Sendromlu Buzağılarda Ultrastrüktürel ve İmmunohistokimyasal İncelemeler

“…The first isolation of BоCV from bronchial secretion and nasopharyngeal washings of calves with signs of pneumonia occurred in 1982 and later, it was determined as bovine respiratory coronavirus (BRCoV) [1,2] . Strains isolated from diarrhoeic newborn calves and cattle have been classified as enteric or enteropathogenic coronaviruses (BECoV) [3] . Тhomas et al [4] affirmed that enteric and respiratory BCoV were the same, although detected in different life cycle stages.…”

“…Тhomas et al [4] affirmed that enteric and respiratory BCoV were the same, although detected in different life cycle stages. They have been isolated from the intestines and lung of calves affected with pneumoenteritis syndrome, and were antigenically and genomically similar [3,4] .…”