A novel defective recombinant porcine enterovirus G virus carrying a porcine torovirus papain-like cysteine protease gene and a putative anti-apoptosis gene in place of viral structural protein genes

Infect Genet Evol. 2019 Nov:75:103975. doi: 10.1016/j.meegid.2019.103975. Epub 2019 Jul 22.


Enterovirus G (EV-G) belongs to the family of Picornaviridae. Two types of recombinant porcine EV-Gs carrying papain-like cysteine protease (PLCP) gene of porcine torovirus, a virus in Coronaviridae, are reported. Type 1 recombinant EV-Gs are detected in pig feces in Japan, USA, and Belgium and carry the PLPC gene at the junction site of 2C/3A genes, while PLPC gene replaces the viral structural genes in type 2 recombinant EV-G detected in pig feces in a Chinese farm. We identified a novel type 2 recombinant EV-G carrying the PLCP gene with flanking sequences in place of the viral structural genes in pig feces in Japan. The ~0.3 kb-long upstream flanking sequence had no sequence homology with any proteins deposited in GenBank, while the downstream ~0.9 kb-long flanking sequence included a domain having high amino acid sequence homology with a baculoviral inhibitor of apoptosis repeat superfamily. The pig feces, where the novel type 2 recombinant EV-G was detected, also carried type 1 recombinant EV-G. The amount of type 1 and type 2 recombinant EV-G genomes was almost same in the pig feces. Although the phylogenetic analysis suggested that these two recombinant EV-Gs have independently evolved, type 1 recombinant EV-G might have served as a helper virus by providing viral structural proteins for dissemination of the type 2 recombinant EV-G.

Keywords: Enterovirus; Recombination; Torovirus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / genetics
  • Apoptosis Regulatory Proteins / metabolism*
  • Cysteine Proteases / genetics*
  • Cysteine Proteases / metabolism
  • Enterovirus Infections / epidemiology
  • Enterovirus Infections / veterinary*
  • Enterovirus Infections / virology
  • Enteroviruses, Porcine / genetics*
  • Feces / virology
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Viral
  • Phylogeny
  • Swine
  • Swine Diseases / epidemiology
  • Swine Diseases / virology
  • Viral Structural Proteins / genetics*


  • Apoptosis Regulatory Proteins
  • Viral Structural Proteins
  • Cysteine Proteases