Linked Life Data

9426142

Source:http://linkedlifedata.com/resource/pubmed/id/9426142

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1998-3-5
pubmed:databankReference
pubmed:abstractText
In Erwinia amylovora, the dsp region, required for pathogenicity on the host plant but not for hypersensitive elicitation on tobacco, is separated from the hrp region by 4 kb. The genetic analysis reported in this paper showed that this 4kb region is not required for pathogenicity on pear seedlings. The environmental conditions allowing expression of a dsp::lacZ fusion were examined: expression was barely detected in rich medium at 30 degrees C, and the highest expression was observed in M9 galactose minimal medium at 25 degrees C. A dsp::uidA fusion appeared to be expressed only in a HrpL-proficient strain, indicating that the dsp region, like the hrp region, is positively controlled via the alternative a factor HrpL. Sequence analysis revealed that the dsp cluster encodes two genes, dspA (5517 bp) and dspB (420 bp), and that the insertions leading to the dsp::lacZ and the dsp::uidA fusions were within dspA. A HrpL-dependent promoter sequence (GGAACC-N15-CAACA) was identified upstream of dspA, and primer extension analysis detected four transcriptional starts 7, 8, 9 and 10 bp downstream of this sequence. A sigma70 promoter sequence (TTGCCC-N16-GATAAT) was observed upstream of dspB. The functionality of this second promoter was confirmed by complementation analysis. This promoter allowed constitutive expression of dspB, as measured by the expression of a dspB::uidA fusion in rich medium. In M9 galactose medium, however, HrpL was shown to activate dspB, as expression of the dspB::uidA fusion was twofold higher in a HrpL+ background than in a HrpL- background. Transposon insertions in either dspA or dspB led to a non-pathogenic phenotype. Thus, both DspA and DspB were required for E. amylovora pathogenicity, as dspB could be expressed independently of dspA. DspA and DspB were visualized as polypeptides with apparent sizes of 190 kDa and 15.5 kDa, respectively, when encoded in the T7 polymerase/promoter system. DspA, which showed homology with the protein predicted from the partial sequence of Pseudomonas syringae pv. tomato avrE transcriptional unit III, was shown to be secreted into the external medium via the Hrp secretion pathway. DspB was predicted to be acidic, like the Syc chaperone of Yersinia. A chaperone role for DspB was suggested further by the fact that DspA secretion required a functional DspB protein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
26
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1057-69
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:9426142-Amino Acid Sequence, pubmed-meshheading:9426142-Bacterial Proteins, pubmed-meshheading:9426142-Base Sequence, pubmed-meshheading:9426142-Binding Sites, pubmed-meshheading:9426142-Cosmids, pubmed-meshheading:9426142-DNA, Bacterial, pubmed-meshheading:9426142-DNA-Binding Proteins, pubmed-meshheading:9426142-DNA-Directed RNA Polymerases, pubmed-meshheading:9426142-Erwinia, pubmed-meshheading:9426142-Gene Expression Regulation, Bacterial, pubmed-meshheading:9426142-Molecular Sequence Data, pubmed-meshheading:9426142-Multigene Family, pubmed-meshheading:9426142-Promoter Regions, Genetic, pubmed-meshheading:9426142-Pseudomonas, pubmed-meshheading:9426142-Recombinant Fusion Proteins, pubmed-meshheading:9426142-Sequence Homology, Amino Acid, pubmed-meshheading:9426142-Sigma Factor, pubmed-meshheading:9426142-Temperature, pubmed-meshheading:9426142-Transcription, Genetic, pubmed-meshheading:9426142-Viral Proteins, pubmed-meshheading:9426142-Virulence
pubmed:year
1997
pubmed:articleTitle
DspA, an essential pathogenicity factor of Erwinia amylovora showing homology with AvrE of Pseudomonas syringae, is secreted via the Hrp secretion pathway in a DspB-dependent way.
pubmed:affiliation
Laboratoire de pathologie végétale INA-PG/INRA, Paris, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't