The U3 and Env Proteins of Jaagsiekte Sheep Retrovirus and Enzootic Nasal Tumor Virus Both Contribute to Tissue Tropism

Viruses. 2019 Nov 14;11(11):1061. doi: 10.3390/v11111061.


Jaagsiekte sheep retrovirus (JSRV) and enzootic nasal tumor virus (ENTV) are small-ruminant betaretroviruses that share high nucleotide and amino acid identity, utilize the same cellular receptor, hyaluronoglucosaminidase 2 (Hyal2) for entry, and transform tissues with their envelope (Env) glycoprotein; yet, they target discrete regions of the respiratory tract-the lung and nose, respectively. This distinct tissue selectivity makes them ideal tools with which to study the pathogenesis of betaretroviruses. To uncover the genetic determinants of tropism, we constructed JSRV-ENTV chimeric viruses and produced lentivectors pseudotyped with the Env proteins from JSRV (Jenv) and ENTV (Eenv). Through the transduction and infection of lung and nasal turbinate tissue slices, we observed that Hyal2 expression levels strongly influence ENTV entry, but that the long terminal repeat (LTR) promoters of these viruses are likely responsible for tissue-specificity. Furthermore, we show evidence of ENTV Env expression in chondrocytes within ENTV-infected nasal turbinate tissue, where Hyal2 is highly expressed. Our work suggests that the unique tissue tropism of JSRV and ENTV stems from the combined effort of the envelope glycoprotein-receptor interactions and the LTR and provides new insight into the pathogenesis of ENTV.

Keywords: chimeric virus; envelope glycoproteins; long terminal repeat (LTR), sheep betaretroviruses; pathogenesis; pseudotyping; tropism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Gene Order
  • Gene Products, env / genetics*
  • Genome, Viral
  • Host Specificity
  • Host-Pathogen Interactions
  • Humans
  • Jaagsiekte sheep retrovirus / physiology*
  • Oncogenic Viruses / physiology*
  • Pulmonary Adenomatosis, Ovine / virology*
  • Reassortant Viruses / genetics
  • Sheep
  • Terminal Repeat Sequences*
  • Tumor Virus Infections / virology*
  • Viral Tropism*


  • Gene Products, env