Cell-binding properties of the envelope proteins of porcine endogenous retroviruses.
To examine the binding properties of the envelope glycoproteins of porcine endogenous retrovirus subgroups A and B (PERV-A and PERV-B), we produced two forms of soluble envelope proteins, termed Env-ST and Env-SU, using a baculovirus expression system. Env-ST and Env-SU encompass one-third of the N-terminal and the entire surface unit (SU) of the envelope protein, respectively. Using these proteins, binding assays were performed in various mammalian cell lines. The binding properties of the Env-STs that contain the putative receptor binding domain (RBD) did not correlate with the susceptibility to the pseudotype viruses having PERV envelopes, whereas those of the Env-SUs correlated fairly well. These results suggested that the Env-SUs but not Env-STs interacted with their receptors in various cell lines. Interestingly, PERV-A Env-SU did not bind to a mink cell line (Mv1-Lu cells) that is highly susceptible to the PERV-A pseudotype virus. In addition, PERV-B Env-SU did not interfere with the PERV-B pseudotype virus on Mv1-Lu cells. These results suggest the existence of a cognate receptor-independent entry pathway as demonstrated in an immunodeficiency-inducing variant of feline leukemia virus FeLV.
Watanabe
Rie
R
Research Center for Emerging Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Miyazawa
Takayuki
T
Matsuura
Yoshiharu
Y
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D020077:Endogenous Retroviruses / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D011991:Receptors, Virus / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013552:Swine / Q000821:virology; D014183:Transplantation, Heterologous; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D011991:Receptors, Virus; D011994:Recombinant Proteins; D014759:Viral Envelope Proteins