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Journal of virology1991; 65(6); 2910-2920; doi: 10.1128/JVI.65.6.2910-2920.1991

Equine arteritis virus is not a togavirus but belongs to the coronaviruslike superfamily.

Abstract: The nucleotide sequence of the genome of equine arteritis virus (EAV) was determined from a set of overlapping cDNA clones and was found to contain eight open reading frames (ORFs). ORFs 2 through 7 are expressed from six 3'-coterminal subgenomic mRNAs, which are transcribed from the 3'-terminal quarter of the viral genome. A number of these ORFs are predicted to encode structural EAV proteins. The organization and expression of the 3' part of the EAV genome are remarkably similar to those of coronaviruses and toroviruses. The 5'-terminal three-quarters of the genome contain the putative EAV polymerase gene, which also shares a number of features with the corresponding gene of corona- and toroviruses. The gene contains two large ORFs, ORF1a and ORF1b, with an overlap region of 19 nucleotides. The presence of a "shifty" heptanucleotide sequence in this region and a downstream RNA pseudoknot structure indicate that ORF1b is probably expressed by ribosomal frameshifting. The frameshift-directing potential of the ORF1a/ORF1b overlap region was demonstrated by using a reporter gene. Moreover, the predicted ORF1b product was found to contain four domains which have been identified in the same relative positions in coronavirus and torovirus ORF1b products. The sequences of the EAV and coronavirus ORF1a proteins were found to be much more diverged. The EAV ORF1a product contains a putative trypsinlike serine protease motif. Our data indicate that EAV, presently considered a togavirus, is evolutionarily related to viruses from the coronaviruslike superfamily.
Publication Date: 1991-06-01 PubMed ID: 1851863PubMed Central: PMC240924DOI: 10.1128/JVI.65.6.2910-2920.1991Google Scholar: Lookup
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Summary

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The research article focuses on discovering the characteristics and the structure of the equine arteritis virus (EAV). This study turns the common belief about taxonomy of EAV upside down – rather than being part of the Togaviridae family, it claims that EAV fits better within the superfamily the coronaviruses belong to.

Determining the Genome Sequence

Researchers were able to determine the nucleotide sequence of EAV’s genome using overlapping cDNA clones. Through this, they discovered that the genome contained eight open reading frames (ORFs), proteins that potentially encode for other proteins.

  • ORFs 2 through 7 are expressed from six 3′-coterminal subgenomic mRNAs.
  • These mRNAs are transcribed from the 3′-terminal quarter of the EAV genome.
  • Several of these ORFs, expressed from the 3′-terminal quarter, are anticipated to encode structural EAV proteins.

Similarities with Coronaviruses

The organization and expression patterns found in the 3′ part of the EAV genome are strikingly similar to those of coronaviruses and toroviruses.

  • The 5′-terminal three-quarters of the genome contain the presumed EAV polymerase gene, which also has similarities with the corresponding gene of corona- and toroviruses in several aspects.
  • The gene contains two large ORFs, ORF1a and ORF1b, with overlapping regions of 19 nucleotides.
  • A “shifty” heptanucleotide sequence in this region, together with a downstream RNA pseudoknot structure, suggests that ORF1b is likely expressed by ribosomal frameshifting.
  • The possibility of frameshift was then demonstrated by using a reporter gene.

In addition to these points, researchers found that the derived product of ORF1b contains four domains appearing in the same relative positions as in coronavirus and torovirus ORF1b products.

Divergence in Protein Sequences

Though there are several similarities, one divergence was found in sequences of EAV and coronavirus’ ORF1a proteins, which were discovered to be significantly different from each other.

  • EAV ORF1a product contains a putative trypsinlike serine protease motif.

This research implies an evolutionary link between EAV and the coronavirus superfamily, indicating that EAV likely does not belong to the togavirus family as traditionally thought.

Cite This Article

APA
den Boon JA, Snijder EJ, Chirnside ED, de Vries AA, Horzinek MC, Spaan WJ. (1991). Equine arteritis virus is not a togavirus but belongs to the coronaviruslike superfamily. J Virol, 65(6), 2910-2920. https://doi.org/10.1128/JVI.65.6.2910-2920.1991

Publication

ISSN: 0022-538X
NlmUniqueID: 0113724
Country: United States
Language: English
Volume: 65
Issue: 6
Pages: 2910-2920

Researcher Affiliations

den Boon, J A
  • Department of Virology, Faculty of Medicine, Leiden University, The Netherlands.
Snijder, E J
    Chirnside, E D
      de Vries, A A
        Horzinek, M C
          Spaan, W J

            MeSH Terms

            • Amino Acid Sequence
            • Base Sequence
            • Biological Evolution
            • Coronaviridae / genetics
            • DNA, Viral / chemistry
            • DNA-Directed RNA Polymerases / genetics
            • Equartevirus / genetics
            • Equartevirus / growth & development
            • Gene Expression
            • HeLa Cells / microbiology
            • Humans
            • Molecular Sequence Data
            • Open Reading Frames
            • RNA, Messenger / biosynthesis
            • Ribosomes / metabolism
            • Serine Endopeptidases / chemistry
            • Serine Endopeptidases / genetics
            • Togaviridae / genetics
            • Virion / genetics
            • Virus Replication

            References

            This article includes 50 references
            1. Virology. 1991 Feb;180(2):567-82
              pubmed: 1846489
            2. Virology. 1986 Jul 30;152(2):492-6
              pubmed: 3014727
            3. Virology. 1990 Oct;178(2):355-63
              pubmed: 2219698
            4. J Gen Virol. 1988 Sep;69 ( Pt 9):2135-44
              pubmed: 3411297
            5. Proc Natl Acad Sci U S A. 1988 Apr;85(8):2444-8
              pubmed: 3162770
            6. Nucleic Acids Res. 1989 Jun 26;17(12):4847-61
              pubmed: 2526320
            7. Nucleic Acids Res. 1989 May 25;17(10):3889-97
              pubmed: 2543956
            8. Virology. 1989 Aug;171(2):637-9
              pubmed: 2548336
            9. FEBS Lett. 1989 Jan 30;243(2):103-14
              pubmed: 2645167
            10. Proc Natl Acad Sci U S A. 1988 Nov;85(21):7872-6
              pubmed: 3186696
            11. EMBO J. 1989 Dec 1;8(12):3867-74
              pubmed: 2555175
            12. J Mol Biol. 1985 Mar 20;182(2):317-29
              pubmed: 3889350
            13. Nucleic Acids Res. 1989 Dec 11;17(23):9543-55
              pubmed: 2557586
            14. Proc Natl Acad Sci U S A. 1986 Nov;83(21):8122-6
              pubmed: 3095828
            15. J Gen Virol. 1987 Jan;68 ( Pt 1):57-77
              pubmed: 3027249
            16. Res Vet Sci. 1986 Sep;41(2):279-80
              pubmed: 3022363
            17. Intervirology. 1985;24(3):125-39
              pubmed: 2999027
            18. Intervirology. 1988;29(5):260-7
              pubmed: 3058643
            19. J Gen Virol. 1988 Dec;69 ( Pt 12):2939-52
              pubmed: 3058868
            20. Zentralbl Veterinarmed B. 1986 Aug;33(6):413-7
              pubmed: 2431561
            21. Nucleic Acids Res. 1989 Nov 11;17(21):8413-40
              pubmed: 2555771
            22. Proc Natl Acad Sci U S A. 1989 Jul;86(14):5626-30
              pubmed: 2546161
            23. J Virol. 1989 Nov;63(11):4653-64
              pubmed: 2529379
            24. Cell. 1989 May 19;57(4):537-47
              pubmed: 2720781
            25. Nature. 1988 May 5;333(6168):22-3
              pubmed: 3362205
            26. Nucleic Acids Res. 1986 Jan 10;14(1):217-31
              pubmed: 3511446
            27. J Gen Virol. 1986 Nov;67 ( Pt 11):2475-83
              pubmed: 3783129
            28. Nucleic Acids Res. 1985 Mar 11;13(5):1717-31
              pubmed: 4000943
            29. Nucleic Acids Res. 1990 Aug 11;18(15):4535-42
              pubmed: 2388833
            30. Nucleic Acids Res. 1990 Jun 11;18(11):3241-7
              pubmed: 2162519
            31. Nucleic Acids Res. 1990 Apr 11;18(7):1825-32
              pubmed: 2159623
            32. J Virol. 1990 Mar;64(3):1050-6
              pubmed: 2154591
            33. Virus Genes. 1990 Jul;4(2):121-36
              pubmed: 2402881
            34. Virology. 1990 Aug;177(2):768-71
              pubmed: 2371780
            35. J Virol. 1990 Jan;64(1):331-8
              pubmed: 2293666
            36. Virology. 1982 Apr 30;118(2):345-52
              pubmed: 6283728
            37. Nucleic Acids Res. 1984 Jan 11;12(1 Pt 1):387-95
              pubmed: 6546423
            38. Cornell Vet. 1957 Jan;47(1):69-75
              pubmed: 13397180
            39. Cornell Vet. 1957 Jan;47(1):3-41
              pubmed: 13397177
            40. J Gen Virol. 1983 Sep;64 (Pt 9):1849-58
              pubmed: 6886677
            41. Curr Top Microbiol Immunol. 1982;99:131-63
              pubmed: 7047085
            42. Intervirology. 1978;9(3):129-48
              pubmed: 618831
            43. Arch Gesamte Virusforsch. 1971;33(3):306-18
              pubmed: 4107033
            44. Arch Gesamte Virusforsch. 1973;40(3):177-88
              pubmed: 4633581
            45. Virology. 1976 Aug;73(1):200-5
              pubmed: 183352
            46. Virology. 1975 Dec;68(2):418-25
              pubmed: 173077
            47. EMBO J. 1987 Dec 1;6(12):3779-85
              pubmed: 3428275
            48. J Gen Virol. 1986 Aug;67 ( Pt 8):1543-9
              pubmed: 2426393
            49. Cell. 1988 Nov 4;55(3):447-58
              pubmed: 2846182
            50. Nucleic Acids Res. 1990 Dec 11;18(23):7003-6
              pubmed: 2263459