title: Detection and initial characterization of protein entities consisting of the HIV glycoprotein cytoplasmic C-terminal domain alone.
abstract: Employing antibodies against the cytoplasmic tail of the HIV-1 glycoprotein (Env-CT), in addition to gp160/gp41, we have identified several novel small Env proteins (<25kD) in HIV-1 transfected and infected cells. Mass spectrometric and mutational analyses show that two mechanisms contribute to their generation. Thus the protein, designated Tr-Env-CT (for truncated Env-CT), consists of the C-terminal 139 amino acids (aa) of Env (aa 718-856) with the N-terminal Q718 modified to pyroglutamic acid. It is likely derived from full-length Env protein by proteolytic processing. A further heterogeneous set of slightly larger proteins, termed Env-CT* species, are rather derived from spliced mRNAs containing only those Env C-terminal residues (aa 719-856) which overlap with the second tat and rev coding exons. They are N-terminally extended in the same reading frame. It is conceivable that essential Env-CT functions may be fulfilled by these novel species rather than by the full-length glycoprotein itself.
authors.affiliation: Forschungsschwerpunkt Infektion und Krebs, Deutsches Krebsforschungszentrum, 69120 Heidelberg, Germany. t.pfeiffer@dkfz.de
authors.forename: Tanya
authors.initials: T
authors.lastname: Pfeiffer
authors.forename: Thomas
authors.initials: T
authors.lastname: Ruppert
authors.forename: Heiner
authors.initials: H
authors.lastname: Schaal
authors.forename: Valerie
authors.initials: V
authors.lastname: Bosch
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D004252:DNA Mutational Analysis; D006023:Glycoproteins / Q000032:analysis*; D015497:HIV-1 / Q000737:chemistry* / Q000502:physiology*; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D059748:Proteolysis; D012326:RNA Splicing; D054299:env Gene Products, Human Immunodeficiency Virus / Q000032:analysis*
chemical_list: D006023:Glycoproteins; D054299:env Gene Products, Human Immunodeficiency Virus