PMID- 20015979
OWN - NLM
STAT- MEDLINE
DCOM- 20100317
LR  - 20231213
IS  - 1098-5514 (Electronic)
IS  - 0022-538X (Print)
IS  - 0022-538X (Linking)
VI  - 84
IP  - 5
DP  - 2010 Mar
TI  - RNA-dependent RNA polymerase 6 delays accumulation and precludes meristem 
      invasion of a viroid that replicates in the nucleus.
PG  - 2477-89
LID - 10.1128/JVI.02336-09 [doi]
AB  - The detection of viroid-derived small RNAs (vd-sRNAs) similar to the small 
      interfering RNAs (siRNAs, 21 to 24 nucleotides [nt]) in plants infected by 
      nuclear-replicating members of the family Pospiviroidae (type species, Potato 
      spindle tuber viroid [PSTVd]) indicates that they are inducers and targets of the 
      RNA-silencing machinery of their hosts. RNA-dependent RNA polymerase 6 (RDR6) 
      catalyzes an amplification circuit producing the double-stranded precursors of 
      secondary siRNAs. Recently, the role of RDR6 in restricting systemic spread of 
      certain RNA viruses and precluding their invasion of the apical growing tip has 
      been documented using RDR6-silenced Nicotiana benthamiana (NbRDR6i) plants. Here 
      we show that RDR6 is also engaged in regulating PSTVd levels: accumulation of 
      PSTVd genomic RNA was increased in NbRDR6i plants with respect to the wild-type 
      controls (Nbwt) early in infection, whereas this difference decreased or 
      disappeared in later infection stages. Moreover, in situ hybridization revealed 
      that RDR6 is involved in restricting PSTVd access in floral and vegetative 
      meristems, thus providing firm genetic evidence for an antiviroid RNA silencing 
      mechanism. RNA gel blot hybridization and deep sequencing showed in wt and RDR6i 
      backgrounds that PSTVd sRNAs (i) accumulate to levels paralleling their genomic 
      RNA, (ii) display similar patterns with prevailing 22- or 21-nt plus-strand 
      species, and (iii) adopt strand-specific hot spot profiles along the genomic RNA. 
      Therefore, the surveillance mechanism restraining entry of some RNA viruses into 
      meristems likely also controls PSTVd access in N. benthamiana. Unexpectedly, deep 
      sequencing also disclosed in NbRDR6i plants a profile of RDR6-derived siRNA 
      dominated by 21-nt plus-strand species mapping within a narrow window of the 
      hairpin RNA stem expressed transgenically for silencing RDR6, indicating that 
      minus-strand siRNAs silencing the NbRDR6 mRNA represent a minor fraction of the 
      total siRNA population.
FAU - Di Serio, Francesco
AU  - Di Serio F
AD  - Istituto di Virologia Vegetale (CNR), Unita Organizzativa di Bari, Via Amendola 
      165/A, Bari, Italy.
FAU - Martinez de Alba, Angel-Emilio
AU  - Martinez de Alba AE
FAU - Navarro, Beatriz
AU  - Navarro B
FAU - Gisel, Andreas
AU  - Gisel A
FAU - Flores, Ricardo
AU  - Flores R
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20091216
PL  - United States
TA  - J Virol
JT  - Journal of virology
JID - 0113724
RN  - 0 (Isoenzymes)
RN  - 0 (RNA, Small Interfering)
RN  - EC 2.7.7.48 (RNA-Dependent RNA Polymerase)
SB  - IM
EIN - J Virol. 2010 Jun;84(11):5846
MH  - Base Sequence
MH  - Isoenzymes/genetics/*metabolism
MH  - *Meristem/metabolism/virology
MH  - Molecular Sequence Data
MH  - Nucleic Acid Conformation
MH  - Phenotype
MH  - Plant Leaves/anatomy & histology/physiology
MH  - Plants, Genetically Modified
MH  - RNA Interference
MH  - *RNA, Small Interfering/genetics/metabolism
MH  - RNA-Dependent RNA Polymerase/genetics/*metabolism
MH  - Sequence Analysis, DNA
MH  - Nicotiana/*anatomy & histology/*enzymology/genetics/*virology
MH  - Viroids/genetics/*metabolism
PMC - PMC2820905
EDAT- 2009/12/18 06:00
MHDA- 2010/03/18 06:00
PMCR- 2010/09/01
CRDT- 2009/12/18 06:00
PHST- 2009/12/18 06:00 [entrez]
PHST- 2009/12/18 06:00 [pubmed]
PHST- 2010/03/18 06:00 [medline]
PHST- 2010/09/01 00:00 [pmc-release]
AID - JVI.02336-09 [pii]
AID - 2336-09 [pii]
AID - 10.1128/JVI.02336-09 [doi]
PST - ppublish
SO  - J Virol. 2010 Mar;84(5):2477-89. doi: 10.1128/JVI.02336-09. Epub 2009 Dec 16.