title: Identification of a domain within the human T-cell leukemia virus type 2 envelope required for syncytium induction and replication.
abstract: In vitro infection by human T-cell leukemia virus type 1 and 2 (HTLV-1 and HTLV-2) can result in syncytium formation, facilitating viral entry. Using cell lines that were susceptible to HTLV-2-mediated syncytium formation but were nonfusogenic with HTLV-1, we constructed chimeric envelopes between HTLV-1 and -2 and assayed for the ability to induce syncytia in BJAB cells and HeLa cells. We have identified a fusion domain composed of the first 64 amino acids at the amino terminus of the HTLV-2 transmembrane protein, p21, the retention of which was required for syncytium induction. Construction of replication-competent HTLV genomic clones allowed us to correlate the ability of HTLV-2 to induce syncytia with the ability to replicate in BJAB cells. Differences in the ability to induce syncytia were not due to differences in the levels of total or cell membrane-associated envelope or in the formation of multimers. Therefore, we have localized a fusion domain within the amino terminus of the transmembrane protein of HTLV-2 envelope that is necessary for syncytium induction and viral replication.
authors.affiliation: Department of Microbiology and Immunology, UCLA School of Medicine, Los Angeles, California 90095, USA.
authors.forename: B
authors.initials: B
authors.lastname: Poon
authors.forename: I S
authors.initials: IS
authors.lastname: Chen
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D015686:Gene Products, env / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D015726:Giant Cells; D006367:HeLa Cells; D015367:Human T-lymphotropic virus 2 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008561:Membrane Fusion; D010641:Phenotype; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D015682:Retroviridae Proteins, Oncogenic / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication; D054299:env Gene Products, Human Immunodeficiency Virus
chemical_list: D015686:Gene Products, env; D011993:Recombinant Fusion Proteins; D015682:Retroviridae Proteins, Oncogenic; D014759:Viral Envelope Proteins; D054299:env Gene Products, Human Immunodeficiency Virus; C069569:human T-cell leukemia virus type-II protein gp21