title: Separable mechanisms of attachment and cell uptake during retrovirus infection.
abstract: In the absence of viral envelope gene expression, cells expressing human immunodeficiency virus type 1 (HIV-1) gag and pol, accessory HIV functions, and a vector genome RNA produce and secrete large amount of noninfectious virus-like particles (VLPs) into the conditioned medium. After partial purification, such HIV-1 VLPs can be made infectious in cell-free conditions in vitro by complex formation with lipofection reagents or with the G protein of vesicular stomatitis virus (VSV-G). The resulting in vitro-modified HIV-1 particles are able to infect nondividing cells. Infectivity of envelope-free HIV VLPs can also be induced by prior modification of target cells through exposure to partially purified VSV-G vesicles. Similarly, infection can be carried out by attachment of envelope-free noninfectious VLPs to unmodified cells followed by subsequent treatment of cells with VSV-G. We interpret these findings to indicate that interaction between a viral envelope and a cell surface receptor is not necessary for the initial virus binding to the cells but is required for subsequent cell entry and infection.
authors.affiliation: Center for Molecular Genetics and Department of Pediatrics, University of California San Diego School of Medicine, La Jolla, California 92093-0634, USA.
authors.forename: S
authors.initials: S
authors.lastname: Sharma
authors.forename: A
authors.initials: A
authors.lastname: Miyanohara
authors.forename: T
authors.initials: T
authors.lastname: Friedmann
mesh_terms: D002460:Cell Line; D015685:Fusion Proteins, gag-pol / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D008562:Membrane Glycoproteins; D010714:Phosphatidylethanolamines / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism; D014162:Transfection; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism; D014771:Virion / Q000502:physiology
chemical_list: D015685:Fusion Proteins, gag-pol; C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D010714:Phosphatidylethanolamines; D012367:RNA, Viral; D014759:Viral Envelope Proteins; C020888:1,2-dielaidoylphosphatidylethanolamine