A truncated HTLV-I envelope protein, lacking the hydrophobic membrane anchor domain, is associated with cellular membranes and virions.
The HTLV-I producer cell line C10/MJ2 does not induce syncytium formation with HTLV-I receptor expressing cells. Here we show that this cell line produces a truncated envelope protein, which, because of a premature stop codon, lacks the hydrophobic membrane anchor domain of the transmembrane protein (TM). Despite lacking a membrane anchor this envelope protein is expressed on the cell surface and associated with released virions. However, its incorporation into virions seems less efficient than that of a full-length envelope glycoprotein and some of its released into the cell culture supernatant as soluble surface glycoprotein (SU)-TM complexes. Small amounts of such a truncated envelope glycoprotein were also found in the fusion-competent HTLV-I producer cell line MT2. Premature truncation of HTLV-I envelope proteins in producer cell lines may result from in vitro selection for a less fusogenic phenotype. The association of truncated HTLV-I envelope proteins with virions and cell surfaces may reflect interactions between the SU domain and cellular membranes, possibly with the cellular receptor for HTLV-I.
Carrington
C V
CV
Chester Beatty Laboratories, Institute of Cancer Research, London, United Kingdom.
Weiss
R A
RA
Schulz
T F
TF
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D002462:Cell Membrane / Q000382:microbiology*; D003062:Codon; D004279:DNA, Viral; D015752:Genes, env; D015726:Giant Cells / Q000382:microbiology; D015368:Human T-lymphotropic virus 1 / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D013601:T-Lymphocytes / Q000382:microbiology; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000378:metabolism*; D014771:Virion
D003062:Codon; D004279:DNA, Viral; D010446:Peptide Fragments; D014759:Viral Envelope Proteins