title: A membrane-destabilizing peptide in capsid protein L2 is required for egress of papillomavirus genomes from endosomes.
abstract: Papillomaviruses are internalized via clathrin-dependent endocytosis. However, the mechanism by which viral genomes pass endosomal membranes has not been elucidated. In this report we show that the minor capsid protein L2 is required for egress of viral genomes from endosomes but not for initial uptake and uncoating and that a 23-amino-acid peptide at the C terminus of L2 is necessary for this function. Pseudogenomes encapsidated by L1 and L2 lacking this peptide accumulated in vesicular compartments similar to that observed with L1-only viral particles, and these mutant pseudoviruses were noninfectious. This L2 peptide displayed strong membrane-disrupting activity, induced cytolysis of bacteria and eukaryotic cells in a pH-dependent manner, and permeabilized cells after exogenous addition. Fusions between green fluorescent protein and the L2 peptide integrated into cellular membranes like the wild type but not like C-terminal mutants of L2. Our data indicate that the L2 C terminus facilitates escape of viral genomes from the endocytic compartment and that this feature is conserved among papillomaviruses. Furthermore, the characteristic of this peptide differs from the classical virus-encoded membrane-penetrating peptides.
authors.affiliation: Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-Universität Mainz, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Kämper
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Day
authors.forename: Thorsten
authors.initials: T
authors.lastname: Nowak
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Selinka
authors.forename: Luise
authors.initials: L
authors.lastname: Florin
authors.forename: Jan
authors.initials: J
authors.lastname: Bolscher
authors.forename: Lydia
authors.initials: L
authors.lastname: Hilbig
authors.forename: John T
authors.initials: JT
authors.lastname: Schiller
authors.forename: Martin
authors.initials: M
authors.lastname: Sapp
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D036022:Capsid Proteins / Q000235:genetics*; D002460:Cell Line; D011992:Endosomes / Q000821:virology; D016679:Genome, Viral; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D027383:Papillomaviridae / Q000502:physiology*; D030361:Papillomavirus Infections / Q000821:virology; D014779:Virus Replication
chemical_list: D036022:Capsid Proteins