title: A structure-based mechanism for tRNA and retroviral RNA remodelling during primer annealing.
abstract: To prime reverse transcription, retroviruses require annealing of a transfer RNA molecule to the U5 primer binding site (U5-PBS) region of the viral genome. The residues essential for primer annealing are initially locked in intramolecular interactions; hence, annealing requires the chaperone activity of the retroviral nucleocapsid (NC) protein to facilitate structural rearrangements. Here we show that, unlike classical chaperones, the Moloney murine leukaemia virus NC uses a unique mechanism for remodelling: it specifically targets multiple structured regions in both the U5-PBS and tRNA(Pro) primer that otherwise sequester residues necessary for annealing. This high-specificity and high-affinity binding by NC consequently liberates these sequestered residues--which are exactly complementary--for intermolecular interactions. Furthermore, NC utilizes a step-wise, entropy-driven mechanism to trigger both residue-specific destabilization and residue-specific release. Our structures of NC bound to U5-PBS and tRNA(Pro) reveal the structure-based mechanism for retroviral primer annealing and provide insights as to how ATP-independent chaperones can target specific RNAs amidst the cellular milieu of non-target RNAs.
authors.affiliation: 1] Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA [2] Department of Biology, Georgetown University, Washington DC 20057, USA. [3].
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Miller
authors.affiliation: 1] Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA [2].
authors.forename: F Zehra
authors.initials: FZ
authors.lastname: Yildiz
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Lo
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Victoria M
authors.initials: VM
authors.lastname: D'Souza
mesh_terms: D000818:Animals; D002460:Cell Line; D016679:Genome, Viral / Q000235:genetics; D006801:Humans; D008958:Models, Molecular; D008979:Moloney murine leukemia virus / Q000737:chemistry / Q000235:genetics; D019906:Nuclear Magnetic Resonance, Biomolecular; D019590:Nucleocapsid Proteins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism; D012367:RNA, Viral / Q000737:chemistry* / Q000378:metabolism*; D048348:Reverse Transcription / Q000235:genetics / Q000502:physiology*
chemical_list: D019590:Nucleocapsid Proteins; D012367:RNA, Viral; D012343:RNA, Transfer