A gene encoding an RNase D exonuclease‐like protein is required for post‐transcriptional silencing in <i>Arabidopsis</i>

Glazov, Eugene; Phillips, Kenneth L.; Budziszewski, Gregory J.; Meins, Frederick; Levin, Joshua Z.

doi:10.1046/j.1365-313x.2003.01810.x

Cited by 57 publications

(40 citation statements)

References 48 publications

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“…It did not interfere with our ability to identify reliable reporter lines, however, because transgenes undergoing post-transcriptional silencing have a different expression pattern than SPL3. Whereas the expression of SPL3 increases with time, transgenes undergoing silencing are either permanently silenced very early in shoot development, or display progressively lower levels of expression during shoot growth (de Carvalho et al, 1992;Glazov et al, 2003;Palauqui et al, 1996;Vaucheret et al, 2004). Although it is clear that transgenes expressing transcripts with miRNA-target sites are often subject to RNAi, whether this is also true for endogenous transcripts is less certain.…”

Section: The Function Of Rnai In the Regulation Of Spl3mentioning

confidence: 99%

Temporal regulation of shoot development inArabidopsis thalianabymiR156and its targetSPL3

2006

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SPL3, SPL4 and SPL5 (SPL3/4/5) are closely related members of the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE family of transcription factors in Arabidopsis, and have a target site for the microRNA miR156 in their 3Ј UTR. The phenotype of Arabidopsis plants constitutively expressing miR156-sensitive and miR156-insensitive forms of SPL3/4/5 revealed that all three genes promote vegetative phase change and flowering, and are strongly repressed by miR156. Constitutive expression of miR156a prolonged the expression of juvenile vegetative traits and delayed flowering. This phenotype was largely corrected by constitutive expression of a miR156-insensitive form of SPL3. The juvenile-to-adult transition is accompanied by a decrease in the level of miR156 and an increase in the abundance of SPL3 mRNA. The complementary effect of hasty on the miR156 and SPL3 transcripts, as well as the miR156-dependent temporal expression pattern of a 35S::GUS-SPL3 transgene, suggest that the decrease in miR156 is responsible for the increase in SPL3 expression during this transition. SPL3 mRNA is elevated by mutations in ZIPPY/AGO7, RNA DEPENDENT RNA POLYMERASE 6 (RDR6) and SUPPRESSOR OF GENE SILENCING 3 (SGS3), indicating that it is directly or indirectly regulated by RNAi. However, our results indicate that RNAi does not contribute to the temporal expression pattern of this gene. We conclude that vegetative phase change in Arabidopsis is regulated by an increase in the expression of SPL3 and probably also SPL4 and SPL5, and that this increase is a consequence of a decrease in the level of miR156.

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Section: The Function Of Rnai In the Regulation Of Spl3mentioning

confidence: 99%

Temporal regulation of shoot development inArabidopsis thalianabymiR156and its targetSPL3

2006

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“…Transgene-derived siRNAs are methylated by HUA ENHANCER1 (HEN1) (Boutet et al 2003;Yu et al 2005) and guide sequencespecific ARGONAUTE1 (AGO1)-catalyzed mRNA cleavage (Morel et al 2002;Baumberger and Baulcombe 2005;Qi et al 2005). Additional components have been identified by forward and reverse genetic screens (Table1), including NUCLEAR RNA POLYMERASE IVa (NRPD1a), RNA-DEPENDENT RNA POLYMERASE2 (RDR2), SILENCING DEFECTIVE3 (SDE3), and WERNER EXONUCLEASE (WEX) (Dalmay et al 2001;Glazov et al 2003;Herr et al 2005). The steps at which these proteins act in the PTGS pathway are still not fully understood.…”

Section: Cis-acting Sirnas As An Rna-based Immune Mechanism and A Silmentioning

confidence: 99%

“…Biochemistry (Hiraguri et al 2005) dsRNA-binding protein (Hiraguri et al 2005) Reverse genetics (Adenot et al 2006 RNA stabilizer (Yoshikawa et al 2005) (SDE2) Developmental screen (Peragine et al 2004) WEX WERNER EXONUCLEASE Reverse genetics (Glazov et al 2003) RNaseD exonuclease (Glazov et al 2003) cursor RNA, whereas plant miRNAs derive from individual precursors (Ambros 2004;Bartel 2004;Du and Zamore 2005;Kim 2005 (Du and Zamore 2005). In plants, the length of fold-back stemloops generally is longer than that of animal stem-loops.…”

Section: Micrornas As Endogenous Regulators Of Gene Expressionmentioning

confidence: 99%

Post-transcriptional small RNA pathways in plants: mechanisms and regulations

Vaucheret¹

2006

Genes Dev.

670

510

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For a long period of time, DNA, the support of heredity, and proteins, the actors of the cellular machinery, have been considered the most important components of biological systems. By contrast, RNA was originally considered as an intermediate molecule, bridging the gap between DNA and protein (mRNA), or serving functional roles during splicing (snRNA) and translation (tRNA and rRNA). The recent discovery of an increasing number of large and small non-protein-coding RNAs with specific regulatory roles has changed our view of gene expression. In particular, 20-to 27-nucleotide (nt) small RNAs belonging to two classes, microRNAs (miRNAs) and short interfering RNAs (siRNAs), are known to play essential roles in the four Eukaryote kingdoms (protists, fungi, plants, animals), with the surprising exception of the yeast Saccharomyces cerevisiae. Small RNAs are involved in a variety of phenomena that are essential for genome stability, development, and adaptive responses to biotic and abiotic stresses. Their mode of action also is diverse. They guide DNA elimination during the formation of the macronucleus in protists and heterochromatin assembly in fungi and plants. They target endogenous mRNAs for cleavage and translational repression in plants and animals, and protect both plant and animal cells against virus infection through an RNA-based immune system. They also control the movement of transposable elements at the transcriptional and post-transcriptional level in plants and animals. Cis-acting siRNAs as an RNA-based immune mechanism and a silencing toolBecause small RNAs are repressors of gene expression, small RNA-mediated regulation is often referred to as RNA silencing, gene silencing, or RNA interference (RNAi). RNA silencing was discovered in plants more than 15 years ago during the course of transgenic experiments that eventually led to silencing of the introduced transgene and, in some cases, of homologous endogenous genes or resident transgenes (Matzke et al. 1989;Linn et al. 1990;Napoli et al. 1990;Smith et al. 1990;van der Krol et al. 1990). Gene silencing results from transcription inhibition (transcriptional gene silencing [TGS]) or from RNA degradation (post-transcriptional gene silencing [PTGS]), and correlates with the accumulation of siRNAs corresponding to the silenced promoter or to the degraded RNA, respectively (Hamilton and Baulcombe 1999;Mette et al. 2000). The production of virus-derived siRNAs was observed in response to virus infection (Hamilton and Baulcombe 1999), and plant mutants defective in PTGS were hypersusceptible to virus infection (Mourrain et al. 2000;Dalmay et al. 2001;Qu et al. 2005;Schwach et al. 2005). Studies in worm revealed that mutants defective in RNAi (the animal counterpart of PTGS) lose control of their transposable elements (Ketting et al. 1999). Altogether, these results suggested that the PTGS/RNAi pathway corresponds to an RNA-based immune system that allows cells to control endogenous (transposons) or exogenous (virus, transgenes) nucleic acid invaders through...

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“…The most incisive studies in this area have been genetic, and several authors have selected Arabidopsis thaliana mutants impaired in silencing or HDG silencing of transgenes and endogenous genes. Some of these mutant genes have been identified at a molecular level and they fall into two groups: those affecting the metabolism of RNA, SGS2/SDE1 (Dalmay et al, 2000;Mourrain et al, 2000), SGS3 , AGO1 (Fagard et al, 2000), SDE3 (Dalmay et al, 2001), HEN1 (Boutet et al, 2003), and WEX (Glazov et al, 2003), and those affecting chromatin. The latter group can be further subdivided into genes corresponding to mutants impaired in DNA methylation, including DDM1 (Vongs et al, 1993;Scheid et al, 1998;Jeddeloh et al, 1999;Morel et al, 2000), MET1 (formerly known as DDM2; Vongs et al, 1993;Morel et al, 2000), CMT3 (Lindroth et al, 2001), DRM1 and DRM2 , KYP (Jackson et al, 2002), AGO4 (Zilberman et al, 2003), HDA6/SIL1 (Aufsatz et al, 2002;Probst et al, 2004), and DRD1 (Kanno et al, 2004), and genes corresponding to mutants that are not, including MOM (Amedeo et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

The Arabidopsis HOMOLOGY-DEPENDENT GENE SILENCING1 Gene Codes for an S-Adenosyl-l-Homocysteine Hydrolase Required for DNA Methylation-Dependent Gene Silencing

et al. 2005

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Genes introduced into higher plant genomes can become silent (gene silencing) and/or cause silencing of homologous genes at unlinked sites (homology-dependent gene silencing or HDG silencing). Mutations of the HOMOLOGY-DEPENDENT GENE SILENCING1 (HOG1) locus relieve transcriptional gene silencing and methylation-dependent HDG silencing and result in genome-wide demethylation. The hog1 mutant plants also grow slowly and have low fertility and reduced seed germination. Three independent mutants of HOG1 were each found to have point mutations at the 39 end of a gene coding for S-adenosyl-L-homocysteine (SAH) hydrolase, and hog1-1 plants show reduced SAH hydrolase activity. A transposon (hog1-4) and a T-DNA tag (hog1-5) in the HOG1 gene each behaved as zygotic embryo lethal mutants and could not be made homozygous. The results suggest that the homozygous hog1 point mutants are leaky and result in genome demethylation and poor growth and that homozygous insertion mutations result in zygotic lethality. Complementation of the hog1-1 point mutation with a T-DNA containing the gene coding for SAH hydrolase restored gene silencing, HDG silencing, DNA methylation, fast growth, and normal seed viability. The same T-DNA also complemented the zygotic embryo lethal phenotype of the hog1-4 tagged mutant. A model relating the HOG1 gene, DNA methylation, and methylation-dependent HDG silencing is presented.

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A gene encoding an RNase D exonuclease‐like protein is required for post‐transcriptional silencing in Arabidopsis

Cited by 57 publications

References 48 publications

Temporal regulation of shoot development inArabidopsis thalianabymiR156and its targetSPL3

Temporal regulation of shoot development inArabidopsis thalianabymiR156and its targetSPL3

Post-transcriptional small RNA pathways in plants: mechanisms and regulations

The Arabidopsis HOMOLOGY-DEPENDENT GENE SILENCING1 Gene Codes for an S-Adenosyl-l-Homocysteine Hydrolase Required for DNA Methylation-Dependent Gene Silencing

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