Journal ArticleDOI
Viroid replication is inhibited by alpha-amanitin.
Hans-P. Mühlbach,Heinz L. Sänger +1 more
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TLDR
The inhibitory intracellular concentrations of α-amanitin which are determined suggest the involvement of the nuclear DNA-dependent RNA polymerase II in viroid replication in infected tomato protoplasts.Abstract:
VIROIDS are infectious single-stranded circular RNA molecules1 which cause disease in higher Plants. Although the complete molecular structure of one viroid has recently been established2, the mechanism of viroid replication and patho-genesis is still unknown. The viroid molecule carries insufficient genetic information to code for a complete viroid-specified replicase. Replication must therefore depend on host cell enzymes. We report here the inhibition by α-amanitin, of 3H-uridine incorporation into viroid RNA in infected tomato protoplasts. The inhibitory intracellular concentrations of α-amanitin which we determined suggest the involvement of the nuclear DNA-dependent RNA polymerase II in viroid replication.read more
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Journal ArticleDOI
Viroids and viroid-host interactions.
Ricardo Flores,Carmen Hernández,A. Emilio Martínez de Alba,José-Antonio Daròs,Francesco Di Serio +4 more
TL;DR: Although they induce symptoms in plants similar to those accompanying virus infections, viroids have unique structural, functional, and evolutionary characteristics and could exert their pathogenic effects via RNA silencing.
Journal ArticleDOI
Replicating potato spindle tuber viroid RNA is accompanied by short RNA fragments that are characteristic of post-transcriptional gene silencing
Ioannis Papaefthimiou,Andrew J. Hamilton,Michela Alessandra Denti,David C. Baulcombe,Mina Tsagris,Martin Tabler +5 more
TL;DR: The low molecular weight fraction of tomato plants inoculated with potato spindle tuber viroid (PSTVd) contains a population of short PSTVd-specific RNAs of either polarity, which indicated that the nuclear replicating PSTVD RNA induces post-transcriptional gene silencing.
Journal ArticleDOI
Viroids
TL;DR: Recent progress in understanding viroid biology is summarized, including the possible role of recently identified viroid‐binding host proteins as well as the recent data on the interaction of viroids with one part of the host's defence machinery, the RNA‐mediated gene silencing and how this might be connected to viroid replication and pathogenicity.
Journal ArticleDOI
Involvement of nuclear DNA-dependent RNA polymerases in potato spindle tuber viroid replication: a reevaluation
I.-M. Schindler,H.-P. Mühlbach +1 more
TL;DR: Results demonstrate that the DNA dependent RNA polymerase II is directly involved in PSTVd(+) and (−)RNA synthesis, indicating that PSTVD replication does not depend on the active transcription of chromosomal DNA.
Journal ArticleDOI
Viroids: Survivors from the RNA World?
TL;DR: The properties of viroids that make them candidates for being survivors of the RNA world include those expected for primitive RNA replicons: small size imposed by error-prone replication, high G + C content to increase replication fidelity and structural periodicity for modular assembly into enlarged genomes.
References
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Journal ArticleDOI
Viroids are single-stranded covalently closed circular RNA molecules existing as highly base-paired rod-like structures.
TL;DR: Viroids are uncoated infectious RNA molecules pathogenic to certain higher plants and exhibit high thermal stability, cooperativity, and self-complementarity resulting in a rod-like native structure.
Journal ArticleDOI
Specific Inhibition of Nuclear RNA Polymerase II by α-Amanitin
TL;DR: α-Amanitin, a toxic substance from the mushroom Amanita phalloides, is a potent inhibitor of DNA-dependent RNA polymerase II (the nucleoplasmic form) from sea urchin, rat liver, and calf thymus.
Journal ArticleDOI
Amatoxins, phallotoxins, phallolysin, and antamanide: the biologically active components of poisonous Amanita mushrooms.
Theodor Wieland,Heinz Faulstich +1 more
TL;DR: This review gives a comprehensive account of the molecular toxicology of the bicyclic peptides obtained from the poisonous mushrooms of the genus Amanita, also including the most important analytical data.
Journal ArticleDOI
Nucleotide sequence and secondary structure of potato spindle tuber viroid
Hans J. Gross,Horst Domdey,Christine Lossow,Peter Jank,Manfred Raba,Heidemarie Alberty,Heinz L. Sänger +6 more
TL;DR: The viroid of the potato spindle tuber disease is a covalently closed ring of 359 ribonucleotides that is the first pathogen of a eukaryotic organism for which the complete molecular structure has been established.
Journal ArticleDOI
Role of DNA-Dependent RNA Polymerase III in the Transcription of the tRNA and 5S RNA Genes
TL;DR: The role of RNA polymerase III (III(A) and/or III(B)) in the synthesis of (pre) 4S RNAs and a 5S RNA species is unequivocally demonstrated and rule out nonspecific inhibitory effects in the endogenous systems.