Identification of domains in p27 auxiliary replicase protein essential for its association with the endoplasmic reticulum membranes in Red clover necrotic mosaic virus

The submicroscopic organization of mesophyll cells from tobacco leaves systemically infected with tobacco mosaic virus (TMV) is described. After fixation with glutaraldehyde and osmium tetroxide the arrangement of the TMV particles within the crystalline inclusions is well preserved. Only the ribonucleic acid-containing core of the virus particles is visible in the micrographs. Besides the hexagonal virus crystals, several characteristic types of "inclusion bodies" are definable in the cytoplasm: The so-called fluid crystals seem to correspond to single layers of oriented TMV particles between a network of the endoplasmic reticulum and ribosomes. Unordered groups or well oriented masses of tubes with the diameter of the TMV capsid are found in certain areas of the cytoplasm. A complicated inclusion body is characterized by an extensively branched and folded part of the endoplasmic reticulum, containing in its folds long aggregates of flexible rods. Certain parts of the cytoplasm are filled with large, strongly electron-scattering globules, probably of lipid composition. These various cytoplasmic differentiations and the different forms of presumed virus material are discussed in relation to late stages of TMV reproduction and virus crystal formation.

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Interaction of the Tobacco Mosaic Virus Replicase Protein with the Aux/IAA Protein PAP1/IAA26 Is Associated with Disease Development

Journal of Virology ◽

10.1128/jvi.79.4.2549-2558.2005 ◽

2005 ◽

Vol 79 (4) ◽

pp. 2549-2558 ◽

Cited By ~ 79

Author(s):

Meenu S. Padmanabhan ◽

Sameer P. Goregaoker ◽

Sheetal Golem ◽

Haiymanot Shiferaw ◽

James N. Culver

Keyword(s):

Tobacco Mosaic Virus ◽

Mosaic Virus ◽

Protein S ◽

Helicase Domain ◽

Auxin Response ◽

Disease Symptoms ◽

Developmental Abnormalities ◽

Replicase Protein ◽

Transcriptional Alterations

ABSTRACT Virus-infected plants often display developmental abnormalities that include stunting, leaf curling, and the loss of apical dominance. In this study, the helicase domain of the Tobacco mosaic virus (TMV) 126- and/or 183-kDa replicase protein(s) was found to interact with the Arabidopsis Aux/IAA protein PAP1 (also named IAA26), a putative regulator of auxin response genes involved in plant development. To investigate the role of this interaction in the display of symptoms, a TMV mutant defective in the PAP1 interaction was identified. This mutant replicated and moved normally in Arabidopsis but induced attenuated developmental symptoms. Additionally, transgenic plants in which the accumulation of PAP1 mRNA was silenced exhibit symptoms like those of virus-infected plants. In uninfected tissues, ectopically expressed PAP1 accumulated and localized to the nucleus. However, in TMV-infected tissues, PAP1 failed to accumulate to significant levels and did not localize to the nucleus, suggesting that interaction with the TMV replicase protein disrupts PAP1 localization. The consequences of this interaction would affect PAP1's putative function as a transcriptional regulator of auxin response genes. This is supported by gene expression data indicating that ∼30% of the Arabidopsis genes displaying transcriptional alterations in response to TMV contain multiple auxin response promoter elements. Combined, these data indicate that the TMV replicase protein interferes with the plant's auxin response system to induce specific disease symptoms.

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Three discontinuous loop nucleotides in the 3′ terminal stem-loop are required for Red clover necrotic mosaic virus RNA-2 replication

Virology ◽

10.1016/j.virol.2009.08.005 ◽

2009 ◽

Vol 393 (2) ◽

pp. 346-354 ◽

Cited By ~ 4

Author(s):

Ziming Weng ◽

Zhongguo Xiong

Keyword(s):

Mosaic Virus ◽

Red Clover ◽

Stem Loop ◽

Virus Rna

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Cap-Independent Translational Enhancement by the 3′ Untranslated Region of Red Clover Necrotic Mosaic Virus RNA1

Journal of Virology ◽

10.1128/jvi.77.22.12113-12121.2003 ◽

2003 ◽

Vol 77 (22) ◽

pp. 12113-12121 ◽

Cited By ~ 69

Author(s):

Hiroyuki Mizumoto ◽

Masahiro Tatsuta ◽

Masanori Kaido ◽

Kazuyuki Mise ◽

Tetsuro Okuno

Keyword(s):

Mosaic Virus ◽

Untranslated Region ◽

Red Clover ◽

Luciferase Reporter ◽

Base Substitution ◽

Luciferase Reporter Gene ◽

Stem Loop ◽

Genomic Rnas ◽

Translational Activity ◽

Independent Translation

ABSTRACT Red clover necrotic mosaic virus (RCNMV) is a member of the genus Dianthovirus and has a bipartite positive-sense genomic RNA with 3′ ends that are not polyadenylated. In this study, we show that both genomic RNA1 and RNA2 lack a 5′ cap structure and that uncapped in vitro transcripts of RCNMV RNA1 replicated to a level comparable to that for capped transcripts in cowpea protoplasts. Because the 5′ cap and 3′ poly(A) tail play important roles in the translation of many eukaryotic mRNAs, genomic RNAs of RCNMV should contain an element(s) responsible for 5′ cap- and poly(A) tail-independent translation of viral protein. By using a luciferase reporter assay system in vivo, we showed that the 3′ untranslated region (UTR) of RNA1 alone significantly enhanced translation of the luciferase reporter gene in the absence of the 5′ cap structure. Deletion studies revealed that the middle region (between nucleotides 3596 and 3732) in the 3′ UTR, designated the 3′ translation element of Dianthovirus RNA1 (3′TE-DR1), plays an important role in cap-independent translation. This region contained a stem-loop structure conserved among members of the genera Dianthovirus and Luteovirus. A five-base substitution in the loop abolished cap-independent translational activity, as reported for a luteovirus, indicating that this stem-loop is one of the functional structures in the 3′TE-DR1 involved in cap-independent translation. Finally, we suggest that cap-independent translational activity is required for RCNMV RNA1 replication in protoplasts.

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