scholarly journals Sequence-, Tissue-, and Delivery-Specific Targeting of RNA During Post-Transcriptional Gene Silencing

2002 ◽  
Vol 15 (8) ◽  
pp. 753-763 ◽  
Author(s):  
Ezequiel Balmori-Melian ◽  
Robin M. MacDiarmid ◽  
David L. Beck ◽  
Richard C. Gardner ◽  
Richard L. S. Forster
Keyword(s):  
Gene Silencing ◽  
Mosaic Virus ◽  
Viral Vectors ◽  
Transcriptional Gene Silencing ◽  
Wild Type ◽  
Long Distance ◽  
Post Transcriptional Gene Silencing ◽  
In The Wild ◽  
Long Distance Movement ◽  
White Clover Mosaic Virus

Transgenic Nicotiana benthamiana plants expressing an untranslatable version of the coat protein (CP) gene from the Tamarillo mosaic virus (TaMV) were either resistant to TaMV infection or recovered from infection. These phenotypes were the result of a post-transcriptional gene silencing (PTGS) mechanism that targeted TaMV-CP sequences for degradation. The TaMV-CP sequences were degraded when present in the wild-type TaMV potyvirus, in transgene mRNA, or in chimeric viral vectors based on White clover mosaic virus. The more efficiently targeted region was mapped to a 134-nt segment. Differences were observed in the efficiency of targeting during cell-to-cell and long-distance movement of the chimeric viruses. However, the TaMV-CP sequences do not appear to be targeted for degradation when delivered by biolistics.

scholarly journals Differential Virulence by Strains of Cucumber mosaic virus is Mediated by the 2b Gene

2002 ◽  
Vol 15 (9) ◽  
pp. 947-955 ◽  
Author(s):  
Bu-Jun Shi ◽  
Peter Palukaitis ◽  
Robert H. Symons
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Kinetic Studies ◽  
Transcriptional Gene Silencing ◽  
Long Distance ◽  
Post Transcriptional Gene Silencing ◽  
Subgroup Ii ◽  
2B Protein ◽  
Rna Accumulation ◽  
Long Distance Movement

The approximately 12-kDa 2b protein, encoded by all cucumoviruses, had been shown to play an important role in viral long-distance movement, hypervirulence, and suppression of post-transcriptional gene silencing. The role of the 2b gene in the hypervirulence of Cucumber mosaic virus (CMV) and whether hypervirulence was linked to movement were analyzed using a hybrid virus (CMV-qw), generated by replacing the 2b gene in a subgroup II strain, Q-CMV, with the 2b gene from a subgroup IA strain, WAII-CMV. CMV-qw was more virulent than Q-CMV or WAII-CMV on most of the host plant species tested. Northern blot and nucleotide sequence analyses demonstrated that CMV-qw was stably maintained during the course of infection and upon passage. Kinetic studies revealed that the hypervirulence induced by the hybrid virus was associated with neither increased viral RNA accumulation nor more rapid viral movement per se, suggesting that other functions of the 2b protein are important in determining the hypervirulence.

scholarly journals Dual-layer transposon repression in heads of Drosophila melanogaster

2018 ◽  
Author(s):  
Marius van den Beek ◽  
Bruno da Silva ◽  
Juliette Pouch ◽  
Mohammed el amine Ali Chaouche ◽  
Clément Carré ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Silencing ◽  
Rna Extraction ◽  
Transcript Abundance ◽  
Transcriptional Gene Silencing ◽  
Loss Of Function ◽  
Wild Type ◽  
Rna Molecules ◽  
Post Transcriptional Gene Silencing ◽  
Ping Pong

AbstractpiRNA-mediated repression of transposable elements (TE) in the germline limits the accumulation of heritable mutations caused by their transposition in the genome. It is not clear whether the piRNA pathway plays a functional role in adult, non-gonadal tissues in Drosophila melanogaster. To address this question, we first analyzed the small RNA content of adult Drosophila melanogaster heads. We found that varying amount of piRNA-sized, ping-pong positive molecules in heads correlates with contamination by gonadal tissue during RNA extraction, suggesting that most of piRNAs detected in head sequencing libraries originate from gonads. We next sequenced the heads of wild type and piwi mutants to address whether piwi loss of function would affect the low amount of piRNA-sized, ping-pong negative molecules that are still detected in heads hand-checked to avoid gonadal contamination. We find that loss of piwi does not affect significantly these 24-28 RNA molecules. Instead, we observe increased siRNA levels against the majority of Drosophila transposable element families. To determine the effect of this siRNA level change on transposon expression, we sequenced the transcriptome of wild type, piwi, dicer-2 and piwi, dicer-2 double-mutant fly heads. We find that RNA expression levels of the majority of TE families in piwi or dicer-2 mutants remain unchanged and that TE transcript abundance increases significantly only in piwi, dicer-2 double-mutants. These results lead us to suggest a dual-layer model for TE repression in adult somatic tissues. Piwi-mediated transcriptional gene silencing (TGS) established during embryogenesis constitutes the first layer of TE repression whereas Dicer-2-dependent siRNA-mediated post-transcriptional gene silencing (PTGS) provide a backup mechanism to repress TEs that escape silencing by piwi-mediated TGS.

scholarly journals Rapid induction of transcriptional and post-transcriptional gene silencing using a novel Cucumber mosaic virus vector

2006 ◽  
Vol 23 (3) ◽  
pp. 259-265 ◽  
Author(s):  
Shungo Otagaki ◽  
Makoto Arai ◽  
Akiko Takahashi ◽  
Kazunori Goto ◽  
Jin-Sung Hong ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Virus Vector ◽  
Transcriptional Gene Silencing ◽  
Rapid Induction ◽  
Post Transcriptional Gene Silencing

scholarly journals Soybean Mosaic Virus Resistance in Transgenic Soybean Caused by Post-transcriptional Gene Silencing

2007 ◽  
Vol 57 (2) ◽  
pp. 123-128 ◽  
Author(s):  
Noriyuki Furutani ◽  
Noriko Yamagishi ◽  
Soh Hidaka ◽  
Yoshiaki Shizukawa ◽  
Seiji Kanematsu ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Mosaic Virus ◽  
Virus Resistance ◽  
Soybean Mosaic Virus ◽  
Transcriptional Gene Silencing ◽  
Transgenic Soybean ◽  
Post Transcriptional Gene Silencing

scholarly journals small RNA can move long distances through plant vasculature to influence gene expression in shoot apical meristems

2021 ◽  
Author(s):  
Mark A. A. Minow ◽  
Viktoriya Coneva ◽  
Victoria Lesy ◽  
Max Misyura ◽  
Joseph Colasanti
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Gene Silencing ◽  
Small Rna ◽  
Separate Experiment ◽  
Transcriptional Gene Silencing ◽  
Long Distance ◽  
Regulate Gene Expression ◽  
Post Transcriptional Gene Silencing ◽  
Influence Gene Expression

AbstractIn plants, small RNA (sRNA) can regulate gene expression via post transcriptional gene silencing (PTGS) or through RNA-directed DNA methylation (RdDM) leading to transcriptional gene silencing (TGS). sRNA is mobile throughout the plant, with movement occurring short distances from cell-to-cell as well as long distances through the vasculature via phloem trafficking. The range of long-distance sRNA mediated signaling from the vasculature to the shoot apical meristem (SAM) is not clear. To investigate this, two independent transgenic approaches were used to examine trafficking of phloem-expressed sRNA to the SAM in Arabidopsis thaliana. First, the phloem companion-cell specific promoter SUC2 was used to drive expression of an inverted repeat complementary to FLOWERING LOCUS D (FD), a flowering time regulator expressed exclusively in the SAM. In a separate experiment, the SUC2 promoter was used to express an artificial microRNA (aMiR) designed to target a synthetic CLAVATA3 (CLV3) target in the SAM stem cells. Both systems provide evidence of a phloem-to-SAM sRNA communication axis connecting distal regions of the plant to the stem cells of the SAM, which ultimately gives rise to all shoot tissues, including gametes. Thus, phloem-to-SAM sRNA movement defines an important link between sRNA expressed in distal regions of the plant and the growing shoot. Importantly, phloem-to-SAM sRNA trafficking may allow somatic sRNA to direct SAM RdDM, fixing transient sRNA expression events into stable epigenetic changes.

scholarly journals Cucumber mosaic virus-Plant Interactions: Identification of 3a Protein Sequences Affecting Infectivity, Cell-to-Cell Movement, and Long-distance Movement

2001 ◽  
Vol 14 (3) ◽  
pp. 378-385 ◽  
Author(s):  
Qiubo Li ◽  
Ki Hyun Ryu ◽  
Peter Palukaitis
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Virus Movement ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Plant Interactions ◽  
Wild Type ◽  
Long Distance ◽  
In Trans ◽  
Long Distance Movement

Mutants of the Cucumber mosaic virus (CMV) movement protein (MP) were generated and analyzed for their effects on virus movement and pathogenicity in vivo. Similar to the wild-type MP, mutants M1, M2, and M3, promoted virus movement in eight plant species. Mutant M3 showed some differences in pathogenicity in one host species. Mutant M8 showed some host-specific alterations in movement in two hypersensitive hosts of CMV. Mutant M9 showed altered pathogenicity on three hosts and was temperature sensitive for long-distance movement, demonstrating that cell-to-cell and long-distance movement are distinct movement functions for CMV. Four mutants (M4, M5, M6, and M7) were debilitated from movement in all hosts tested. Mutants M4, M5, and M6 could be complemented in trans by the wild-type MP expressed transgenically, although not by each other or by mutant M9 (at the restrictive temperature). Mutant M7 showed an inability to be complemented in trans. From these mutants, different aspects of the CMV movement process could be defined and specific roles for particular sequence domains assigned. The broader implications of these functions are discussed.

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