Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.21.1 (DNase)
 7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Octopine is released from crown gall tumors as a nutrient source and a signal molecule for the plant pathogen Agrobacterium tumefaciens. Some or all octopine-inducible genes are regulated by a protein called OccR. Primer extension analysis showed that OccR protein represses the occR gene and both represses and activates the occQ operon, which is divergently transcribed from occR. These promoters initiate transcription 46 bp apart. This regulatory system was reconstituted in vitro using purified OccR protein and Escherichia coli RNA polymerase. OccR binds with high affinity to a single site overlapping these promoters. Octopine shortens the DNAase I footprint of OccR and increases the gel mobility of OccR-DNA complexes by relaxing an OccR-incited DNA bend.
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PMID:The A. tumefaciens transcriptional activator OccR causes a bend at a target promoter, which is partially relaxed by a plant tumor metabolite. 158 46

In vitro binding experiments were carried out using (32)P-labeled cells of the virulent Agrobacterium tumefaciens strain B6 and Datura innoxia cells from suspension culture. Binding kinetics showed that adherence of bacteria to Datura cells increased gradually during the first 60 minutes and attained a maximum level within 120 minutes of incubation. Maximum binding occurred at pH 6.0. The presence of Ca(2+) and Mg(2+) reduced binding slightly and EDTA had little effect at concentrations of 0.1 to 10 millimolar. The binding of bacteria to Datura cells was temperature-dependent. Escherichia coli, Salmonella typhimurium, Rhizobium japonicum, and Micrococcus lysodeikticus did not compete with virulent A. tumefaciens strain B6 for binding to Datura cells. The admixture of avirulent A. tumefaciens strain IIBNV6 enhanced adherence of virulent A. tumefaciens strain B6 to Datura cells. Octopine had no effect on the binding of virulent A. tumefaciens strain B6 to Datura cells, but 10 millimolar canavanine was inhibitory. Arginine enhanced the adherence of the bacteria at concentrations higher than 0.1 millimolar. Incubation with DNase, RNase, and lipase did not affect the binding, but protease stimulated the adherence of bacteria to Datura cells. Concanavaline A and soybean lectin had little effect whereas lecithin and lysolecithin enhanced binding slightly. Poly-l-lysine markedly stimulated the bacteria-plant cell adherence. Cells from suspension cultures of pea, vetch, and soybean had a 2- to 3-fold higher binding capacity than Datura cells, whereas cells from wheat, corn, rice, and sorghum had a considerably lower affinity for binding with virulent A. tumefaciens strain B6. Bacterial adherence to plant cells was confirmed by autoradiography and electron microscopy. Autoradiographic analysis showed that bacteria were associated with the cell wall, and that often binding of bacteria was localized. Electron micrographs clearly illustrated a tight association of virulent A. tumefaciens strain B6 cells to the Datura cell wall.
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PMID:In Vitro Binding of Agrobacterium tumefaciens to Plant Cells from Suspension Culture. 1666 Jul 32