A DNA polymerase activity is associated with Cauliflower Mosaic Virus

Menissier, J.; Laquel, Patrica; Lebeurier, G.; Hirth, L.

doi:10.1093/nar/12.23.8769

Cited by 30 publications

(17 citation statements)

References 26 publications

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“…Moreover it can control the complexity of DNA self-entanglement in the form of knots (10,(12)(13)(14). It is useful here to recall that DNA knots have been already reported for some bacteriophages (12,15,16), although it is not yet clear how virus-specific effects (such as the genome anchoring to the capsid) may affect knot type and abundance.…”

Section: Dna Knotting | Monte Carlo Simulationsmentioning

confidence: 94%

Topological friction strongly affects viral DNA ejection

Marenduzzo

Micheletti

Orlandini

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

111

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Bacteriophages initiate infection by releasing their double-stranded DNA into the cytosol of their bacterial host. However, what controls and sets the timescales of DNA ejection? Here we provide evidence from stochastic simulations which shows that the topology and organization of DNA packed inside the capsid plays a key role in determining these properties. Even with similar osmotic pressure pushing out the DNA, we find that spatially ordered DNA spools have a much lower effective friction than disordered entangled states. Such spools are only found when the tendency of nearby DNA strands to align locally is accounted for. This topological or conformational friction also depends on DNA knot type in the packing geometry and slows down or arrests the ejection of twist knots and very complex knots. We also find that the family of (2, 2k+1) torus knots unravel gradually by simplifying their topology in a stepwise fashion. Finally, an analysis of DNA trajectories inside the capsid shows that the knots formed throughout the ejection process mirror those found in gel electrophoresis experiments for viral DNA molecules extracted from the capsids.DNA knotting | Monte Carlo simulations B acteriophages are viruses which infect bacteria. They mostly rely on a remarkably simple infection strategy: after landing on the host cell wall, they release their genetic material into its cytoplasm and hijack the cell protein networks to aid capsid formation and phage replication. For double-stranded DNA (dsDNA)-based phages the infection is initiated by the very large pressure (∼10 atm) (1) to which the DNA is subject inside the capsid, where it is packaged to almost crystalline density by a powerful molecular motor (2). Because of the opposing osmotic pressure from the macromolecules in the bacterial cytosol, the later stages of the DNA ejection process in vivo often rely on the host cellular machinery to finalize the viral genome delivery.Although existing theories have stressed the importance of salt-induced interactions and electrostatics on the ejection time (3, 4) these usually underestimate the conformational entropy contribution to the packaging or ejection force by exclusively considering one optimized, ordered DNA arrangement. The impact of highly variable DNA-packing conformations on the ejection process is thus not accounted for a priori.To better understand the impact that DNA spatial arrangement has on its ejection kinetics we consider the ordering effects of local DNA-DNA interactions. We concentrate in particular on the known tendency of contacting dsDNA strands to align at a small angle with respect to each other (regardless of the 3′-5′ orientation in each of the strands). Increasing evidence shows that this cholesteric interaction is not only important for the formation of cholesteric phases in concentrated solutions of DNA (5-8) but can favor the spool-like DNA arrangements of viral DNA (9-11) inside small capsids. Moreover it can control the complexity of DNA self-entanglement in the form of knots (10,(12)(13)(14...

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Section: Dna Knotting | Monte Carlo Simulationsmentioning

confidence: 94%

Topological friction strongly affects viral DNA ejection

Marenduzzo

Micheletti

Orlandini

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

111

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“…Some gpIV may be present as disulfidelinked dimers (Al Ani et al, 1979b;Martínez-lzquierdo and Hohn, 1987). Virions are also believed to contain some gplll (Giband et al, 1986;Mesnard et al, 1990) and gpV (e.g., Ménissier et al, 1984) as minor components.…”

Section: Introductionmentioning

confidence: 99%

Cauliflower mosaic virus: A 420 subunit (T = 7), multilayer structure

1992

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The structures of the Cabb-B and CM 1841 strains of cauliflower mosaic virus (CaMV) have been solved to about 3 nm resolution from unstained, frozen-hydrated samples that were examined with low-irradiation cryo-electron microscopy and three-dimensional image reconstruction procedures. CaMV is highly susceptible to distortions. Spherical particles, with a maximum diameter of 53.8 nm, are composed of three concentric layers (I-III) of solvent-excluded density that surround a large, solvent-filled cavity (∼27 nm dia.). The outermost layer (I) contains 72 capsomeric morphological units, with 12 pentavalent pentamers and 60 hexavalent hexamers for a total of 420 subunits (37-42 kDa each) arranged with T = 7 icosahedral symmetry. CaMV is the first example of a T = 7 virus that obeys the rules of stoichiometry proposed for isometric viruses by Caspar and Klug (1962, Cold Spring Harb. Symp. Quant. Biol. 27, 1-24), although the hexameric capsomers exhibit marked departure from the regular sixfold symmetry expected for a structure in which the capsid protein subunits are quasi-equivalently related. The double-stranded DNA genome is distributed in layers II and III along with a portion of the viral protein. The CaMV reconstructions are consistent with the model based on neutron diffraction studies (Kruse et al., 1987, Virology 159, 166-168) and, together, these structural models are discussed in relation to a replicationassembly model (Hull et al., 1987, J. Cell Sci. (Suppl.) 7, 213-229). Remarkable agreement between the reconstructions of CaMV Cabb-B and CM1841 suggests that other strains of CaMV adopt the Same basic Structure.

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“…The only form present in virions, pl 1, lacks DNA-binding activity (Giband et al, 1986). The product of ORF V, reverse transcriptase, is a minor virion component (Menissier et al, 1984) that should have an affinity for RNA and ssDNA. Reverse transcriptases form dimers but not higher order aggregates (Lightfoote et al, 1986;Veronese et al, 1986).…”

Section: Discussionmentioning

confidence: 99%

“…These particles contain CaMV RNA and coat protein (Marsh & Guilfoyle, 1987). They also contain DNA strands heterogeneous in size (Marsh et al, 1985;Thomas et al, 1985) and, when provided deoxynucleoside triphosphates in vitro, can elongate those strands (Laquel et al, 1986;Mazzolini et at., 1989;Menissier et al, 1984). These observations suggest that CaMV DNA synthesis requires prior formation of a complex of coat protein and singlestranded 35S RNA.…”

Section: Introductionmentioning

confidence: 92%