Ectopic expression of vaccinia virus E3 and K3 cannot rescue ectromelia virus replication in rabbit RK13 cells

PLoS One. 2015 Mar 3;10(3):e0119189. doi: 10.1371/journal.pone.0119189. eCollection 2015.

Abstract

As a group, poxviruses have been shown to infect a wide variety of animal species. However, there is individual variability in the range of species able to be productively infected. In this study, we observed that ectromelia virus (ECTV) does not replicate efficiently in cultured rabbit RK13 cells. Conversely, vaccinia virus (VACV) replicates well in these cells. Upon infection of RK13 cells, the replication cycle of ECTV is abortive in nature, resulting in a greatly reduced ability to spread among cells in culture. We observed ample levels of early gene expression but reduced detection of virus factories and severely blunted production of enveloped virus at the cell surface. This work focused on two important host range genes, named E3L and K3L, in VACV. Both VACV and ECTV express a functional protein product from the E3L gene, but only VACV contains an intact K3L gene. To better understand the discrepancy in replication capacity of these viruses, we examined the ability of ECTV to replicate in wild-type RK13 cells compared to cells that constitutively express E3 and K3 from VACV. The role these proteins play in the ability of VACV to replicate in RK13 cells was also analyzed to determine their individual contribution to viral replication and PKR activation. Since E3L and K3L are two relevant host range genes, we hypothesized that expression of one or both of them may have a positive impact on the ability of ECTV to replicate in RK13 cells. Using various methods to assess virus growth, we did not detect any significant differences with respect to the replication of ECTV between wild-type RK13 compared to versions of this cell line that stably expressed VACV E3 alone or in combination with K3. Therefore, there remain unanswered questions related to the factors that limit the host range of ECTV.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Ectopic Gene Expression
  • Ectromelia virus / genetics*
  • Epithelial Cells / pathology
  • Epithelial Cells / virology
  • Gene Expression Regulation, Viral*
  • Host Specificity
  • Kidney / pathology
  • Kidney / virology
  • Mice
  • RNA-Binding Proteins / genetics*
  • RNA-Binding Proteins / metabolism
  • Rabbits
  • Vaccinia virus / genetics*
  • Vaccinia virus / pathogenicity
  • Viral Proteins / genetics*
  • Viral Proteins / metabolism
  • Virus Replication

Substances

  • E3L protein, Ectromelia virus
  • E3L protein, Vaccinia virus
  • K3L protein, Ectromelia virus
  • RNA-Binding Proteins
  • Viral Proteins
  • pK3 protein, Vaccinia virus

Grant support

This work was supported through the Albright Creative Research Experience (ACRE) program and other internal funding from Albright College. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.