Mechanisms underlying glycosylation-mediated loss of ecotropic receptor function in murine MDTF cells and implications for receptor evolution.
A Mus dunni tail fibroblast (MDTF) cell line is highly resistant to infection by ecotropic Moloney murine leukemia virus (Mo-MLV). The cationic amino acid transporter type 1 (CAT1) paralogues of murine NIH 3T3 and MDTF cells (mCAT1 and dCAT1, respectively) contain two conserved N-linked glycosylation sites in the third extracellular loop (ECL3, the putative Mo-MLV binding site). Glycosylation of dCAT1 inhibits Mo-MLV infection, but that of mCAT1 does not. Compared with mCAT1, dCAT1 possesses an Ile-to-Val substitution at position 214 and a Gly insertion at position 236 in the ECL3. To determine the residues responsible for the loss of dCAT1 receptor function, mutants of mCAT1 were constructed. The mCAT1/insG receptor (with a Gly residue inserted at mCAT1 position 236) had greatly reduced Mo-MLV receptor function compared with mCAT1. Treatment of mCAT1/insG-expressing cells with tunicamycin, an N-linked glycosylation inhibitor, increased the transduction titre. In addition, the reduced susceptibility to Mo-MLV observed with mCAT1/insG-expressing cells correlated with impaired binding of Mo-MLV. These results show that a single amino acid insertion confers mCAT1 receptor properties on dCAT1 and provide an important insight into the co-evolution of virus-host interactions.
Yoshii
Hiroaki
H
Department of Preventive and Therapeutic Research for Infectious Diseases, Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.|Department of AIDS Research, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
Kamiyama
Haruka
H
Department of AIDS Research, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
Amanuma
Hiroshi
H
Molecular Cell Science Laboratory, RIKEN, Saitama, Japan.
Oishi
Kazunori
K
International Research Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.|Department of Preventive and Therapeutic Research for Infectious Diseases, Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
Yamamoto
Naoki
N
AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan.|Department of AIDS Research, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
Kubo
Yoshinao
Y
Department of AIDS Research, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D017124:Conserved Sequence; D019143:Evolution, Molecular; D005347:Fibroblasts / Q000378:metabolism* / Q000821:virology*; D006031:Glycosylation; D006801:Humans; D007942:Leukemia, Experimental / Q000235:genetics / Q000821:virology; D008297:Male; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000235:genetics / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D051381:Rats; D011991:Receptors, Virus / Q000172:deficiency / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D008562:Membrane Glycoproteins; D011991:Receptors, Virus; C070506:ecotropic murine leukemia virus receptor