title: Intracellular nucleic acid delivery by the supercharged dengue virus capsid protein.
abstract: Supercharged proteins are a recently identified class of proteins that have the ability to efficiently deliver functional macromolecules into mammalian cells. They were first developed as bioengineering products, but were later found in the human proteome. In this work, we show that this class of proteins with unusually high net positive charge is frequently found among viral structural proteins, more specifically among capsid proteins. In particular, the capsid proteins of viruses from the Flaviviridae family have all a very high net charge to molecular weight ratio (> +1.07/kDa), thus qualifying as supercharged proteins. This ubiquity raises the hypothesis that supercharged viral capsid proteins may have biological roles that arise from an intrinsic ability to penetrate cells. Dengue virus capsid protein was selected for a detailed experimental analysis. We showed that this protein is able to deliver functional nucleic acids into mammalian cells. The same result was obtained with two isolated domains of this protein, one of them being able to translocate lipid bilayers independently of endocytic routes. Nucleic acids such as siRNA and plasmids were delivered fully functional into cells. The results raise the possibility that the ability to penetrate cells is part of the native biological functions of some viral capsid proteins.
authors: Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
authors: João Miguel
authors: JM
authors: Freire
authors: Ana Salomé
authors: AS
authors: Veiga
authors: Thaís M
authors: TM
authors: Conceição
authors: Wioleta
authors: W
authors: Kowalczyk
authors: Ronaldo
authors: R
authors: Mohana-Borges
authors: David
authors: D
authors: Andreu
authors: Nuno C
authors: NC
authors: Santos
authors: Andrea T
authors: AT
authors: Da Poian
authors: Miguel A R B
authors: MA
authors: Castanho
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D036022:Capsid Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D003716:Dengue Virus / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism* / Q000821:virology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D012367:RNA, Viral / Q000737:chemistry / Q000378:metabolism*; D053586:Virus Internalization
chemical_list: D036022:Capsid Proteins; D012367:RNA, Viral