Linked Life Data

10375627

Source:http://linkedlifedata.com/resource/pubmed/id/10375627

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1999-8-5
pubmed:abstractText
Haemophilus ducreyi, which causes the genital ulcer disease chancroid, requires high basal levels of the 60-kDa heat-shock (hs) protein GroEL in order to survive and adhere to host cells in the presence of common environmental stresses. In contrast, the 70-kDa hs protein, DnaK, a negative modulator of the hs response in prokaryotes, is not produced at as high a level as GroEL. Because of these differences, we were interested in identifying regulatory elements affecting the expression of the H. ducreyi dnaK/dnaJ operon. First, the genes encoding H. ducreyi DnaK (Hsp70) and DnaJ (Hsp40) were sequenced. The deduced amino acid sequences shared 82.8 and 63. 9% identity with the Escherichia coli DnaK and DnaJ homologs, respectively. Despite the presence of highly similar (but not identical) hs promoter sequences preceding both the H. ducreyi groES/groEL and dnaK/dnaJ operons, transcription levels for groEL were found to exceed that of dnaK. Subsequently, other genetic elements that could contribute to a lower basal expression of dnaK in H. ducreyi were identified. These elements include: (1) a complex promoter for dnaK consisting of four transcriptional start points (two for sigma32 and two for sigma70) identified by primer extension; (2) a putative binding site for Fur (a transcriptional repressor of iron-regulated genes) that overlaps the initiating AUG of dnaK; and (3) the potential for extensive secondary structure of the long leader sequences of the dnaK transcripts, which could interfere with efficient translation of DnaK. This unique combination of regulatory elements may be responsible for the relatively low-level expression of dnaK in this fastidious genital pathogen.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0378-1119
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
233
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
109-19
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:10375627-Amino Acid Sequence, pubmed-meshheading:10375627-Base Sequence, pubmed-meshheading:10375627-Chaperonin 60, pubmed-meshheading:10375627-Cloning, Molecular, pubmed-meshheading:10375627-DNA Primers, pubmed-meshheading:10375627-Escherichia coli Proteins, pubmed-meshheading:10375627-HSP40 Heat-Shock Proteins, pubmed-meshheading:10375627-HSP70 Heat-Shock Proteins, pubmed-meshheading:10375627-Haemophilus ducreyi, pubmed-meshheading:10375627-Heat-Shock Proteins, pubmed-meshheading:10375627-Molecular Sequence Data, pubmed-meshheading:10375627-Nucleic Acid Conformation, pubmed-meshheading:10375627-Operon, pubmed-meshheading:10375627-Promoter Regions, Genetic, pubmed-meshheading:10375627-RNA, Messenger, pubmed-meshheading:10375627-Sequence Homology, Amino Acid, pubmed-meshheading:10375627-Transcription, Genetic
pubmed:year
1999
pubmed:articleTitle
The dnaK/dnaJ operon of Haemophilus ducreyi contains a unique combination of regulatory elements.
pubmed:affiliation
Wadsworth Center, New York State Department of Health, Albany, New York, and School of Public Health, Department of Biomedical Sciences, University at Albany, Albany, NY 12208, USA. parsons@wadsworth.org
pubmed:publicationType
Journal Article