title: Functional characterization of the putative hepatitis B virus core protein late domain using retrovirus chimeras.
abstract: The hepatitis B virus (HBV) Core protein encodes a late (L)-domain like motif (129PPAYRPPNAP(138)) that has been purported to serve as a docking site for recruitment of host factors such as Nedd4 that can mediate viral particle release from infected cells. However, mutation of this region of Core typically disrupts nucleocapsid formation in the cytoplasm, making it difficult to ascertain if the Core PPAY motif constitutes a functional L-domain that mediates HBV release in the context of replicating virus. Since many viral L-domains are functionally interchangeable between different virus families, and such swapping experiments have been used as a tool to identify other viral sequences with L-domain activity, we generated chimeric constructs between murine leukemia virus (MLV) Gag and HBV Core to determine if the potential HBV L-domain motif is sufficient to stimulate virus release. We found that the HBV Core PPAY motif, but not the PNAP motif, demonstrates L-domain activity in the context of MLV replication to direct virus release and infectious virion production. Additionally, we found that overexpression of the cellular Nedd4 or WWP1 ubiquitin ligases stimulates release of a partially defective PPAY domain mutant, providing further evidence supporting a role for the Nedd4 ubiquitin ligase in promoting HBV release. These studies lend further insight into the mechanisms used by HBV to mediate its release from infected cells.
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA.
authors.forename: Mayra L
authors.initials: ML
authors.lastname: Garcia
authors.forename: Tracy D
authors.initials: TD
authors.lastname: Reynolds
authors.forename: Walther
authors.initials: W
authors.lastname: Mothes
authors.forename: Michael D
authors.initials: MD
authors.lastname: Robek
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D056827:Endosomal Sorting Complexes Required for Transport / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D023061:Gene Order; D015683:Gene Products, gag / Q000378:metabolism*; D006515:Hepatitis B virus / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D009052:Leukemia Virus, Murine / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D000075702:Nedd4 Ubiquitin Protein Ligases; D010446:Peptide Fragments / Q000494:pharmacology; D054730:Protein Interaction Domains and Motifs / Q000235:genetics; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014758:Viral Core Proteins / Q000737:chemistry / Q000378:metabolism*; D057074:Virus Release / Q000187:drug effects
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D015683:Gene Products, gag; D010446:Peptide Fragments; D014758:Viral Core Proteins; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618483:Nedd4 protein, human; C000618461:Nedd4l protein, mouse; D044767:Ubiquitin-Protein Ligases