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

A 25-kb DNA region, previously cloned from Pseudomonas syringae pv. syringae 61 in cosmid pHIR11, enables nonpathogenic bacteria such as Pseudomonas fluorescens and Escherichia coli to elicit the hypersensitive response (HR) in tobacco (Nicotiana tabacum). hrmA is located within this region, adjacent to a conserved cluster of hrp genes, and is essential for nonpathogens to elicit the HR. DNA sequence analysis suggested that hrmA was the second of two genes in an operon and was preceded by an open reading frame (ORF), ORF1, which is predicted to encode a 10.9-kDa protein. DNA gel blot analysis revealed that sequences hybridizing with a DNA fragment internal to hrmA were absent from P. syringae pv. syringae B728a, P. syringae pv. tabaci 11528, and P. syringae pv. glycinea race 4 U1, but present in P. syringae pv. tomato DC3000. A 2.4-kb BamHI-AvrII fragment carrying hrmA, ORF1, and native regulatory sequences was subcloned into broad-host-range vector pDSK519 and electroporated into P. syringae pv. syringae B728a and P. syringae pv. tabaci 11528. The presence of the hrmA locus had no apparent effect on the ability of P. syringae pv. syringae B728a to cause brown spot of bean, but it caused P. syringae pv. tabaci 11528 to elicit the defense-associated HR rather than disease in N. tabacum cvs. Xanthi N and Xanthi NC and N. clevelandii. Furthermore, N. debeyii, N. glutinosa, N. rustica, and N. tabacum cvs. Petit Havana and Samsun responded with the HR to P. fluorescens(pHIR11). In contrast, N. benthamiana-P. syringae pv. tabaci interactions were unaffected by the presence of HrmA, and P. fluorescens(pHIR11) did not elicit the HR in N. benthamiana. The hrmA ORF was subcloned into pFLAG-CTC, which expressed HrmA with a C-terminal FLAG synthetic epitope fusion. Escherichia coli MC4100 cells carrying the functional hrp cluster and the hrmA-FLAG derivative secreted the HrpZ harpin, but not HrmA-FLAG, to the medium, as indicated by immunoblot analysis with M2 anti-FLAG and polyclonal anti-HrpZ antibodies. The hrmA ORF was also subcloned into plant expression vector pFF19 and then biolistically delivered, along with pFF19G (expressing beta-glucuronidase), into suspension-cultured tobacco cells. Histochemical staining 24 h later revealed substantial beta-glucuronidase activity in cells receiving pFF19G and pFF19 but not in those receiving pFF19G and pFF19-HrmA. Thus, internal production of HrmA was deleterious to tobacco cells.
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PMID:Evidence that the Pseudomonas syringae pv. syringae hrp-linked hrmA gene encodes an Avr-like protein that acts in an hrp-dependent manner within tobacco cells. 920 63

Using mini-Tn5CmR::gusA, a transposon that allows transcriptional fusions to a promoterless beta-glucuronidase gene, a mutant of Erwinia carotovora subsp. carotovora SCC3193 deficient in extracellular protease production and soft-rot pathogenicity in plants was isolated. The mutant, designated SCC6004, produced normal levels of pectate lyase, polygalacturonase and cellulase. The region of the transposon insertion was partially sequenced to permit the design of specific oligonucleotide primers to amplify a 2.7 kb Clal fragment from E. carotovora subsp. carotovora SCC3193. The DNA sequence of the cloned fragment contained two complete and one partial ORFs. One of the complete ORFs (ORF1) was designated prtW and encodes a secreted protease. The deduced amino acid sequence of PrtW showed a high overall identify of 60-66% to the previously described Erwinia chrysanthemi proteases, but no homology to other proteases isolated from different E. carotovora strains. Downstream from ORF1, a further complete ORF (ORF2) and a partial ORF (ORF3) were found, with deduced peptide sequences that have significant similarity to the Inh and PrtD proteins, respectively, from E. chrysanthemi, which are involved in protease secretion. Gene fusion to the gusA reporter was employed to charaterize the regulation of prtW. The prtW gene was found to be strongly induced in the presence of plant extracts. The mutant exhibited reduced virulence, suggesting that PrtW enhances the ability of strain SCC3193 to macerate plant tissue.
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PMID:Isolation of an extracellular protease gene of Erwinia carotovora subsp. carotovora strain SCC3193 by transposon mutagenesis and the role of protease in phytopathogenicity. 1046 62