Sequences for two cDNAs encoding Arabidopsis thaliana eukaryotic protein synthesis initiation factor 4A

Metz, Anneke M.; Timmer, Richard T.; Browning, Karen S.

doi:10.1016/0378-1119(92)90112-3

Cited by 48 publications

(35 citation statements)

References 5 publications

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“…The transfers were hybridized with 32 P-labeled probes for either the entire CBF1 coding sequence or the COR15a gene. After autoradiography, the transfers were hybridized a second time with the constitutively expressed eIF-4A (eukaryotic Initiation Factor 4A) gene (32) to confirm that RNA loading and transfer were uniform between the samples (data not shown). The autoradiograms for the COR15a and CBF1 probes were exposed for 1 h and 5 days, respectively.…”

Section: Discussionmentioning

confidence: 99%

Arabidopsis thaliana CBF1 encodes an AP2 domain-containing transcriptional activator that binds to the C-repeat/DRE, a cis-acting DNA regulatory element that stimulates transcription in response to low temperature and water deficit

Stockinger

Gilmour

Thomashow

1997

Proc. Natl. Acad. Sci. U.S.A.

1,588

1,203

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Recent efforts have defined a cis-acting DNA regulatory element in plants, the C-repeat͞dehydration responsive element (DRE), that stimulates transcription in response to low temperature and water deficit. Here we report the isolation of an Arabidopsis thaliana cDNA that encodes a C-repeat͞DRE binding factor, CBF1 (C-repeat͞DRE Binding Factor 1). Analysis of the deduced CBF1 amino acid sequence indicates that the protein has a molecular mass of 24 kDa, a potential nuclear localization sequence, and a possible acidic activation domain. CBF1 also has an AP2 domain, which is a DNA-binding motif of about 60 aa present in the Arabidopsis proteins APETALA2, AINTEGUMENTA, and TINY; the tobacco ethylene response element binding proteins; and numerous other plant proteins of unknown function. The transcript levels for CBF1, which appears to be a single or low copy number gene, did not change appreciably in plants exposed to low temperature or in detached leaves subjected to water deficit. Binding of CBF1 to the C-repeat͞DRE was demonstrated in gel shift assays using recombinant CBF1 protein expressed in Escherichia coli. Moreover, expression of CBF1 in yeast was found to activate transcription of reporter genes containing the C-repeat͞DRE as an upstream activator sequence but not mutant versions of the DNA element. We conclude that CBF1 can function as a transcriptional activator that binds to the C-repeat͞DRE DNA regulatory element and, thus, is likely to have a role in cold-and dehydrationregulated gene expression in Arabidopsis.

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Section: Discussionmentioning

confidence: 99%

Arabidopsis thaliana CBF1 encodes an AP2 domain-containing transcriptional activator that binds to the C-repeat/DRE, a cis-acting DNA regulatory element that stimulates transcription in response to low temperature and water deficit

Stockinger

Gilmour

Thomashow

1997

Proc. Natl. Acad. Sci. U.S.A.

1,588

1,203

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“…Control hybridization of tobacco with an actin probe was carried out following published procedures (40). Arabidopsis RNA was hybridized with a eukaryotic protein synthesis initiation factor 4A (eIF-4A) fragment from Arabidopsis (41). Analysis of NOSpro dsRNA and small RNA was carried out as described (11).…”

Section: Methodsmentioning

confidence: 99%

RNA-directed DNA methylation inArabidopsis

Aufsatz

Mette

Winden

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

241

230

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In plants, double-stranded RNA that is processed to short RNAs Ϸ21-24 nt in length can trigger two types of epigenetic gene silencing. Posttranscriptional gene silencing, which is related to RNA interference in animals and quelling in fungi, involves targeted elimination of homologous mRNA in the cytoplasm. RNAdirected DNA methylation involves de novo methylation of almost all cytosine residues within a region of RNA-DNA sequence identity. RNA-directed DNA methylation is presumed to be responsible for the methylation observed in protein coding regions of posttranscriptionally silenced genes. Moreover, a type of transcriptional gene silencing and de novo methylation of homologous promoters in trans can occur if a double-stranded RNA contains promoter sequences. Although RNA-directed DNA methylation has been described so far only in plants, there is increasing evidence that RNA can also target genome modifications in other organisms. To understand how RNA directs methylation to identical DNA sequences and how changes in chromatin configuration contribute to initiating or maintaining DNA methylation induced by RNA, a promoter double-stranded RNA-mediated transcriptional gene silencing system has been established in Arabidopsis. A genetic analysis of this system is helping to unravel the relationships among RNA signals, DNA methylation, and chromatin structure.T he term ''RNA silencing'' refers to epigenetic gene silencing effects that are initiated by double-stranded RNA (dsRNA) (1). Discovered independently in plants, fungi, and animals, RNA silencing phenomena are revealing new ways to repress gene expression and to subdue transposable elements and viruses that produce dsRNA during their replication cycle (2-8). A fundamental step in RNA silencing pathways is cleavage of dsRNA into short RNAs (9), which are believed to act as guides for enzyme complexes that either degrade or modify homologous nucleic acids.The most familiar type of RNA silencing occurs primarily in the cytoplasm and is termed posttranscriptional gene silencing (PTGS) in plants, quelling in Neurospora, and RNA interference (RNAi) in animals. PTGS͞RNAi involves a dsRNA that is processed by an RNase III-like enzyme called Dicer into short interfering (si) RNAs 21-22 nt in length. The antisense siRNAs associate with a ribonuclease complex and guide sequencespecific degradation of complementary mRNAs (5-8).A second form of RNA silencing involves sequence-specific changes at the genome level. RNA-directed DNA methylation (RdDM) (10), which has been described so far only in plants, leads to de novo methylation of almost all cytosine residues within the region of sequence identity between the triggering RNA and the target DNA. Similarly to PTGS͞RNAi, RdDM requires a dsRNA that is cleaved to short RNAs Ϸ21-24 nt in length (11). It is not yet certain whether the short RNAs or dsRNA guide methylation of homologous DNA sequences, although the length of short RNAs is consistent with the minimum DNA target size of RdDM (Ϸ30 bp) (12).RdDM is assumed to be the ...

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“…Plants were either grown at 20°C (W) or at 20°C and then cold treated at 5°C for 7 d (C). eIF4a (eukaryotic initiation factor 4a) is a constitutively expressed gene used as a loading control (Metz et al, 1992). Upon long exposure, CBF3 transcripts can be detected in the total RNA samples prepared from cold-treated Ws-2 and B6 plants (not shown).…”

Section: Identification Of Transgenic Arabidopsis Plants That Overexpmentioning

confidence: 99%

Overexpression of the ArabidopsisCBF3Transcriptional Activator Mimics Multiple Biochemical Changes Associated with Cold Acclimation

et al. 2000

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We further investigated the role of the Arabidopsis CBF regulatory genes in cold acclimation, the process whereby certain plants increase in freezing tolerance upon exposure to low temperature. The CBF genes, which are rapidly induced in response to low temperature, encode transcriptional activators that control the expression of genes containing the C-repeat/ dehydration responsive element DNA regulatory element in their promoters. Constitutive expression of either CBF1 or CBF3 (also known as DREB1b and DREB1a, respectively) in transgenic Arabidopsis plants has been shown to induce the expression of target COR (cold-regulated) genes and to enhance freezing tolerance in nonacclimated plants. Here we demonstrate that overexpression of CBF3 in Arabidopsis also increases the freezing tolerance of cold-acclimated plants. Moreover, we show that it results in multiple biochemical changes associated with cold acclimation: CBF3-expressing plants had elevated levels of proline (Pro) and total soluble sugars, including sucrose, raffinose, glucose, and fructose. Plants overexpressing CBF3 also had elevated P5CS transcript levels suggesting that the increase in Pro levels resulted, at least in part, from increased expression of the key Pro biosynthetic enzyme ⌬ 1 -pyrroline-5-carboxylate synthase. These results lead us to propose that CBF3 integrates the activation of multiple components of the cold acclimation response.

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Sequences for two cDNAs encoding Arabidopsis thaliana eukaryotic protein synthesis initiation factor 4A

Cited by 48 publications

References 5 publications

Arabidopsis thaliana CBF1 encodes an AP2 domain-containing transcriptional activator that binds to the C-repeat/DRE, a cis-acting DNA regulatory element that stimulates transcription in response to low temperature and water deficit

Arabidopsis thaliana CBF1 encodes an AP2 domain-containing transcriptional activator that binds to the C-repeat/DRE, a cis-acting DNA regulatory element that stimulates transcription in response to low temperature and water deficit

RNA-directed DNA methylation inArabidopsis

Overexpression of the ArabidopsisCBF3Transcriptional Activator Mimics Multiple Biochemical Changes Associated with Cold Acclimation

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