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Refrex-1, a soluble restriction factor against feline endogenous and exogenous retroviruses

Jumpei Ito1, Shinya Watanabe, Takahiro Hiratsuka

  • 1Laboratory of Molecular Immunology and Infectious Disease, Joint Faculty of Veterinary Medicine.

Journal of Virology
|August 23, 2013
PubMed

Insights

Researchers discovered Refrex-1, a soluble antiretroviral factor in cats, which inhibits specific feline endogenous gammaretroviruses (ERV-DCs) and novel FeLV-D strains. This factor may be crucial for feline antiviral defense.

Area of Science:

  • Virology
  • Immunology
  • Genetics

Background:

  • Host defense against viral infections involves coevolution with pathogens.
  • Cellular factors restricting retroviral infections are known in hosts.
  • Feline endogenous gammaretroviruses (ERV-DCs) are hereditary in cats and can be replication-competent.

Purpose of the Study:

  • To identify new viral receptor interference groups for feline leukemia virus (FeLV).
  • To discover novel antiretroviral factors involved in feline host defense.
  • To characterize the mechanism of action and expression of these factors.

Main Methods:

  • Analysis of FeLV-D strains and ERV-DCs to determine receptor interference groups.
  • Characterization of Refrex-1 as a truncated envelope protein of ERV-DC.
  • Investigation of Refrex-1 secretion and its effect on receptor interference.
  • Analysis of Refrex-1 variants encoded by provirus loci (ERV-DC7, DC16) in feline tissues.

Main Results:

  • Two new viral receptor interference groups distinct from other FeLV subgroups were identified.
  • A soluble antiretroviral factor, Refrex-1, was discovered and specifically inhibited one of these groups.
  • Refrex-1 is a secreted, truncated ERV-DC envelope protein that acts extracellularly.
  • Two Refrex-1 variants are expressed in various feline tissues.

Conclusions:

  • Refrex-1 acts as a soluble antiretroviral factor in cats, potentially preventing the reemergence of ERVs.
  • This factor may play a significant role in retroviral restriction and antiviral defense in the feline host.
  • Refrex-1 might have been acquired during the endogenization of ERV-DCs, contributing to long-term host defense.

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