The Viruses and Their Taxonomy

Francki, R. I. B.

doi:10.1007/978-1-4684-4937-2_1

Cited by 19 publications

(8 citation statements)

References 48 publications

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“…There must be biological advantages for the formation of particles that are not limited by a defined internal volume of an icosahedral shell. Comparison of virions displayed by members of the Bromoviridae demonstrates a likely evolutionary path for the development of pleomorphic particles that are not restricted with regard to their RNA content [2]. Particles of this type are frequently observed as nucleoprotein cores in animal viruses and it remains to be seen if there is any relation between the subunits forming these particles and those that form the pleomorphic plant virions.…”

Section: Structural Basis Of Polymorphism In Ccmv Assembliesmentioning

confidence: 99%

“…CCMV is a member of the bromovirus group of the Bromoviridae family. Tripartite genomes, encapsulated in polyhedral or bacilliform particles, distinguish the 31 member Bromoviridae family from other plant virus taxa [2]. The CCMV genome consists of three unique, single-stranded, positive-sense RNA molecules which are encapsidated separately.…”

Section: Introductionmentioning

confidence: 99%

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Structures of the native and swollen forms of cowpea chlorotic mottle virus determined by X-ray crystallography and cryo-electron microscopy

et al. 1995

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The CCMV capsid displays quaternary structural interactions that are unique compared with previously determined RNA virus structures. The loosely coupled hexamer and pentamer morphological units readily explain their versatile reassembly properties and the pH and metal ion dependent polymorphism observed in the virions. Association of capsomeres through inter-penetrating carboxy-terminal portions of the subunit polypeptides has been previously described only for the DNA tumor viruses, SV40 and polyoma.

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Section: Structural Basis Of Polymorphism In Ccmv Assembliesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structures of the native and swollen forms of cowpea chlorotic mottle virus determined by X-ray crystallography and cryo-electron microscopy

et al. 1995

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“…Prunus necrotic ringspot virus (PNRSV) is found worldwide infecting a wide range of Prunus species. It belongs to the Ilarvirus genus, the members of which are characterized by having a tripartite genome and quasi‐isometric particles (Francki, 1985). PNRSV is phylogenetically closely related to prune dwarf virus (PDV) and apple mosaic virus (ApMV) (Sánchez‐Navarro & Pallás, 1997).…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of ELISA, nonradioactive molecular hybridization and PCR for the detection of prunus necrotic ringspot virus in herbaceous and Prunus hosts

et al. 1998

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Three methods were compared for the detection of prunus necrotic ringspot virus in herbaceous and woody plants: DAS-ELISA, nonisotopic dot-blot hybridization and reverse transcriptional polymerase chain reaction (RT-PCR). When purified virus preparations were used, the detection limit of the RT-PCR technique was 1·28 pg mL ¹1 whereas nonisotopic molecular hybridization and DAS-ELISA allowed detection of 0·8 ng mL ¹1 and 4 ng mL ¹1 , respectively. Several sample processing procedures were evaluated for virus detection by the nonisotopic molecular hybridization technique. When a very short and simple sample processing method was used, the detection limit of the nonisotopic molecular hybridization technique was 25 times higher than that of DAS-ELISA and 625 times lower than that of RT-PCR. A comparison of the level of virus accumulation in mature fruits and in leaf tissue showed that, on average, 125 times more virus was found in the fruits. Materials and Methods Plant and virus sourcePetals from a field-grown PNRSV-infected nectarine (Prunus persica) tree were homogenized and served as inoculum for cucumber (Cucumis sativus cv. National Pickling) plants. After several passages, virus was Plant Pathology (1998) 47, 780-786 780 ᮊ 1998 BSPP

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“…Since the particle structures of cucumoviruses and the molecular masses of their coat protein subunits are similar (Francki, 1985;Palukaitis et al, 1992), the question arises as to whether coat protein subunits of two different cucumoviruses can combine in the same capsid to produce a particle with a mixedsubunit capsid. In this paper, we show that particles comprising coat protein subunits of both TAV (strain V, V-TAV) and CMV (strain T, T-CMV) can assemble in vitro.…”

mentioning

confidence: 99%

Mixed-subunit capsids can be assembled in vitro with coat protein subunits from two cucumoviruses

Chen

Randles

Francki

1995

Journal of General Virology

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Virus particles were reassembled in vitro from tomato aspermy virus strain V (V-TAV) RNA and a mixture of subunits prepared from V-TAV and 3~S-labelled cucumber mosaic virus strain T (T-CMV). Immunodiffusion tests showed that the reassembled particles reacted with polyclonal antisera raised against both V-TAV and T-CMV. Radioactivity was found in the precipitin line formed between the reassembled particles and antiserum raised against T-CMV as well as in the precipitin line formed between the reassembled particles and antiserum raised against V-TAV. This shows that 35S-labelled T-CMV protein subunits were incorporated with V-TAV protein subunits into the same particles. Thus, coat proteins of V-TAV and T-CMV can coassemble and form mixed-subunit capsids in vitro.The coat protein subunits of two cucumoviruses, cucumber mosaic virus (CMV) and tomato aspermy virus (TAV), can encapsidate each other's RNA in vitro, as well as the RNA of tobacco mosaic virus (Chen & Francki, 1990). Since the particle structures of cucumoviruses and the molecular masses of their coat protein subunits are similar (Francki, 1985; Palukaitis et al., 1992), the question arises as to whether coat protein subunits of two different cucumoviruses can combine in the same capsid to produce a particle with a mixedsubunit capsid. In this paper, we show that particles comprising coat protein subunits of both TAV (strain V, V-TAV) and CMV (strain T, T-CMV) can assemble in vitro.To label T-CMV coat protein, 2.5 mCi ~5SO~-(in 1 ml of aqueous solution; Amersham) was applied directly to the roots of Nicotiana clevelandii plants infected with T-CMV and showing the first signs of systemic symptoms (5-7 days post-inoculation). The plants were then kept under continuous light for 6-8 days (Hajimorad, 1989). Unlabelled T-CMV and V-TAV were propagated in N. clevelandii in the glasshouse. Both the labelled and unlabelled viruses were purified as described previously (Francki et al., 1979) and the viral RNAs were isolated by phenol extraction (Peden & Symons, 1973 T-CMV protein was prepared from 1,5 mg T-CMV (0"3 mg 35S-labelled virus mixed with 1.2 mg unlabelled virus). V-TAV protein was prepared from 1.5 mg of V-TAV. T-CMV protein and V-TAV protein (each 0.7 mg) were mixed with 0.35 mg of V-TAV RNA in a total volume of 3-32 ml. The mixture was dialysed against assembly buffer (20 mM-Tris-HC1 pH 7.2, containing 80 mM-KC1, 1 mM-DTT and 1 mM-MgC12) for 16 h at 4 °C (Chen& Francki, 1990). The mixture was analysed by sucrose density gradient centrifugation. Virus preparations were examined in a JEM 100CX electron microscope after staining with 1% uranyl acetate (Hatta & Francki, 1984). The antiserum raised against T-CMV was previously cross-absorbed with V-TAV by adding 1 mg of the virus to 1 ml of the antiserum, incubating at room temperature for 3 h, and pelleting the virusantiserum complex by centrifugation at 370000g for 15 min. This cross-absorption procedure was done twice. The antiserum raised against V-TAV was cross-absorbed with T-CMV by the same method...

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The Viruses and Their Taxonomy

Cited by 19 publications

References 48 publications

Structures of the native and swollen forms of cowpea chlorotic mottle virus determined by X-ray crystallography and cryo-electron microscopy

Structures of the native and swollen forms of cowpea chlorotic mottle virus determined by X-ray crystallography and cryo-electron microscopy

Comparative analysis of ELISA, nonradioactive molecular hybridization and PCR for the detection of prunus necrotic ringspot virus in herbaceous and Prunus hosts

Mixed-subunit capsids can be assembled in vitro with coat protein subunits from two cucumoviruses

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