Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Systematic protein-DNA binding studies have shown that plant basic leucine zipper (bZIP) proteins exhibit a differential binding specificity for ACGT motifs. Here, we show that the rice transcription activator-1 (RITA-1) displays a broad binding specificity for palindromic ACGT elements, being able to bind A-, C-, and G-box but not T-box elements. By using gel mobility shift assays with probes differing in sequences flanking the hexameric core, we identified high-affinity A-, C-, and G-box binding sites. Quantitative and competition DNA binding studies confirmed RITA-1 specificity for these sites. Using rice protoplasts as a transient expression system, we demonstrated that RITA-1 can transactivate reporter genes possessing high-affinity but not low-affinity RITA-1 binding sites. Our results established a direct relationship between in vivo transactivation and in vitro binding activity. Transient expression assays that demonstrated the ability of RITA-1 to transactivate a construct containing rita-1 5' flanking sequences suggest that the factor may be autoregulated. Histochemical analysis of transgenic rice plants showed that a rita-1-beta-glucuronidase transgene is expressed in aleurone and endosperm cells of developing rice seeds. We propose that RITA-1 plays a role in the regulation of rice genes expressed in developing rice seeds.
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PMID:The rice bZIP transcriptional activator RITA-1 is highly expressed during seed development. 791 92

Calmodulin (CaM) regulates diverse cellular functions by modulating the activities of a variety of enzymes and proteins. However, direct modulation of transcription factors by CaM has been poorly understood. In this study, we isolated a putative transcription factor by screening a rice cDNA expression library by using CaM:horse-radish peroxidase as a probe. This factor, which we have designated OsCBT (Oryza sativa CaM-binding transcription factor), has structural features similar to Arabidopsis AtSRs/AtCAMTAs and encodes a 103-kDa protein because it contains a CG-1 homology DNA-binding domain, three ankyrin repeats, a putative transcriptional activation domain, and five putative CaM-binding motifs. By using a gel overlay assay, gel mobility shift assays, and site-directed mutagenesis, we showed that OsCBT has two different types of functional CaM-binding domains, an IQ motif, and a Ca(2+)-dependent motif. To determine the DNA binding specificity of OsCBT, we employed a random binding site selection method. This analysis showed that OsCBT preferentially binds to the sequence 5'-TWCG(C/T)GTKKKKTKCG-3' (W and K represent A or C and T or G, respectively). OsCBT was able to bind this sequence and activate beta-glucuronidase reporter gene expression driven by a minimal promoter containing tandem repeats of these sequences in Arabidopsis leaf protoplasts. Green fluorescent protein fusions of two putative nuclear localization signals of OsCBT, a bipartite and a SV40 type, were predominantly localized in the nucleus. Most interestingly, the transcriptional activation mediated by OsCBT was inhibited by co-transfection with a CaM gene. Taken together, our results suggest that OsCBT is a transcription activator modulated by CaM.
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PMID:Isolation of a calmodulin-binding transcription factor from rice (Oryza sativa L.). 1619 80

*Plant pathogenic bacteria of the genus Xanthomonas inject transcription activator-like effector (TALe) proteins that bind to and activate host promoters, thereby promoting disease or inducing plant defense. TALes bind to corresponding UPT (up-regulated by TALe) promoter boxes via tandemly arranged 34/35-amino acid repeats. Recent studies uncovered the TALe code in which two amino acid residues of each repeat define specific pairing to UPT boxes. *Here we employed the TALe code to predict potential UPT boxes in TALe-induced host promoters and analyzed these via beta-glucuronidase (GUS) reporter and electrophoretic mobility shift assays (EMSA). *We demonstrate that the Xa13, OsTFX1 and Os11N3 promoters from rice are induced directly by the Xanthomonas oryzae pv. oryzae TALes PthXo1, PthXo6 and AvrXa7, respectively. We identified and functionally validated a UPT box in the corresponding rice target promoter for each TALe and show that box mutations suppress TALe-mediated promoter activation. Finally, EMSA demonstrate that code-predicted UPT boxes interact specifically with corresponding TALes. *Our findings show that variations in the UPT boxes of different rice accessions correlate with susceptibility or resistance of these accessions to the bacterial blight pathogen.
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PMID:Promoter elements of rice susceptibility genes are bound and activated by specific TAL effectors from the bacterial blight pathogen, Xanthomonas oryzae pv. oryzae. 2034 43