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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many plants, including Arabidopsis, show increased resistance to freezing after they have been exposed to low nonfreezing temperatures. This response, termed cold acclimation, is associated with the induction of COR (cold-regulated) genes mediated by the C-repeat/drought-responsive element (CRT/DRE) DNA regulatory element. Increased expression of Arabidopsis CBF1, a transcriptional activator that binds to the CRT/DRE sequence, induced COR gene expression and increased the freezing tolerance of nonacclimated Arabidopsis plants. We conclude that CBF1 is a likely regulator of the cold acclimation response, controlling the level of COR gene expression, which in turn promotes tolerance to freezing.
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PMID:Arabidopsis CBF1 overexpression induces COR genes and enhances freezing tolerance. 955 51

Cold-induced expression of the Arabidopsis COR (cold-regulated) genes is mediated by a DNA regulatory element termed the CRT (C-repeat)/DRE (dehydration-responsive element). Recently, we identified a transcriptional activator, CBF1, that binds to the CRT/DRE and demonstrated that its overexpression in transgenic Arabidopsis plants at non-acclimating temperatures induces COR gene expression and increases plant freezing tolerance. Here we report that CBF1 belongs to a small family of closely related proteins which includes CBF2 and CBF3. DNA sequencing of an 8.7 kb region of the Arabidopsis genome along with genetic mapping experiments indicated that the three CBF genes are organized in direct repeat on chromosome 4 at 72.8 cM, closely linked to molecular markers PG11 and m600. Like CBF1, both CBF2 and CBF3 activated expression of reporter genes in yeast that contained the CRT/DRE as an upstream activator sequence. The transcript levels for all three CBF genes increased within 15 min of transferring plants to low temperature, followed by accumulation of COR gene transcripts at about 2 h. CBF transcripts also accumulated rapidly in response to mechanical agitation. The promoter regions of the CBF genes do not contain the CRT sequence, CCGAC, and overexpression of CBF1 did not have a detectable effect on CBF3 transcript levels, suggesting that the CBF gene family is not subject to autoregulation. We propose that cold-induced expression of CRT/DRE-containing COR genes involves a low temperature-stimulated signalling cascade in which CBF gene induction is an early event.
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PMID:Low temperature regulation of the Arabidopsis CBF family of AP2 transcriptional activators as an early step in cold-induced COR gene expression. 988 Nov 63

The ARABIDOPSIS CBF transcriptional activators bind to the CRT/DRE regulatory element present in the promoters of many cold-regulated genes and stimulate their transcription. Expression of the CBF1 proteins in yeast activates reporter genes carrying a minimal promoter with the CRT/DRE as an upstream regulatory element. Here we report that this ability of CBF1 is dependent upon the activities of three key components of the yeast Ada and SAGA complexes, namely the histone acetyltransferase (HAT) Gcn5 and the transcriptional adaptor proteins Ada2 and Ada3. This result suggested that CBF1 might function through the action of similar complexes in ARABIDOPSIS In support of this hypothesis we found that ARABIDOPSIS has a homolog of the GCN5 gene and two homologs of ADA2, the first report of multiple ADA2 genes in an organism. The ARABIDOPSIS GCN5 protein has intrinsic HAT activity and can physically interact in vitro with both the ARABIDOPSIS ADA2a and ADA2b proteins. In addition, the CBF1 transcriptional activator can interact with the ARABIDOPSIS GCN5 and ADA2 proteins. We conclude that ARABIDOPSIS encodes HAT-containing adaptor complexes that are related to the Ada and SAGA complexes of yeast and propose that the CBF1 transcriptional activator functions through the action of one or more of these complexes.
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PMID:Transcriptional adaptor and histone acetyltransferase proteins in Arabidopsis and their interactions with CBF1, a transcriptional activator involved in cold-regulated gene expression. 1126 54

Four orthologues of the Arabidopsis CBF/Dreb transcriptional activator genes were isolated from the winter Brassica napus, cv. Jet neuf. All four BNCBF clones encode a putative DRE/CRT (LTRE)-binding protein with an AP2 DNA-binding domain, a putative nuclear localization signal and a possible acidic activation domain. Deduced amino acid sequences suggested that BNCBFs 5, 7and 16 are very similar to the Arabidopsis CBFI whereas BNCBF17 is different in that it contains two extra regions of 16 and 21 amino acids in the acidic domain. Transcripts hybridizing specifically to BNCBF17 and to one or more of the other BNCBFs accumulated in leaves within 30 min of cold exposure of the Brassica seedlings and preceded transcript accumulation of the cold-inducible BN28 gene, a Brassica orthologue of the cor6.6 or KIN gene from Arabidopsis. Cold-induced accumulation of BNCBF17 mRNA was rapid but was short-lived compared to transcripts hybridizing to BNCBF5/7/16. Transcripts hybridizing to one or more of BNCBF5/7/16 accumulated at low levels after the plants were subjected to prolonged exposure to salt stress. BNCBF17 was not responsive to salt stress. BNCBF transcript accumulation was similar in both spring and winter Brassica but the persistence of the transcripts in the cold were generally shorter in the spring than in the winter type. BNCBF5 and 17 proteins bind in vitro to the LTRE domains of the cold-inducible BN115 (cor15a orthologue) or BN28 promoters. Differential binding preferences, however, to LTREs between BNI 15 and BN28 were observed. Mutation of the core CCGAC sequence of the LTRE indicated that BNCBF17 had a lower sequence binding specificity than BNCBF5. Furthermore, experiments indicated that the LTREs were able to drive BNCBF5 and 17 trans-activation of the Lac-Z reporter gene in yeast. We conclude that the BNCBFs reported here could function as trans-acting factors in low-temperature responses in Brassica, controlling the expression of cold-induced genes through an ABA-independent pathway.
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PMID:Regulation and characterization of four CBF transcription factors from Brassica napus. 1209 Jun 22

Rice (Oryza sativa L.) is sensitive to chilling particularly at early stages of seedling establishment. Two closely related genes (OsLti6a, OsLti6b), which are induced by low temperature during seedling emergence were isolated from a cold tolerant temperate japonica rice cultivar. These genes are closely related to the Arabidopsis rare cold-inducible (RCI2) and barley low-temperature-inducible (BLT101) genes. Based on direct biochemical and indirect physiological evidence and similarity with a conserved protein domain in the Cluster of Orthologous Groups (COG) database (e.g., yeast PMP3), the rice genes belong to a class of low-molecular-weight hydrophobic proteins involved in maintaining the integrity of the plasma membrane during cold, dehydration and salt stress conditions. Both genes exhibit a genotype-specific expression signature characterized by early and late stress-inducible expression in tolerant and intolerant genotypes, respectively. The differences in temporal expression profiles are consistent with cultivar differences in cold-induced membrane leakiness and seedling vigor. The presence of CRT/DRE promoter cis-elements is consistent with the synchronized expression of OsLti6 genes with the C-repeat binding factor/drought responsive element-binding protein (CBF/DREB) transcriptional activator. The present results indicate that the Oslti6 genes are part of a battery of cold stress defense-related genes regulated by a common switch.
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PMID:The OsLti6 genes encoding low-molecular-weight membrane proteins are differentially expressed in rice cultivars with contrasting sensitivity to low temperature. 1565 83