Characterization of stress-responsive genes, hrcA-grpE-dnaK-dnaJ, from phytopathogenic Xanthomonas campestris.
Sequencing of a 6.4-kb DNA fragment, cloned from the plant pathogenic bacterium Xanthomonas campestris pv. campestris 17 revealed five ORFs whose deduced amino acid sequences show strong similarities to the bacterial HrcA, GrpE, DnaK, DnaJ, and PdxK. The four heat shock genes are organized in the order hrcA-grpE-dnaK-dnaJ, a genome organization found in many gram-positive bacteria, but only in one gram-negative species (Xylella fastidiosa). These observations suggest that the HrcA-CIRCE system, comprising at least four genes arranged in this order, already existed for the regulation of stress responses before bacteria diverged into gram-negative and gram-positive groups. Primer-extension results suggested the presence of promoters at the regions upstream of grpE and dnaK. In the presence of stress, heat or ethanol (4%), the X. campestris pv. campestris 17 grpE and dnaK promoters were induced two- to three-fold over controls. Since the grpE and dnaK promoters possess E. coli sigma(32) promoter-like sequences, they are functional in E. coli, although at levels much lower than in X. campestris pv. campestris 17. Furthermore, expression of the X. campestris pv. campestris 17 dnaK promoter in E. coli was elevated by the cloned X. campestris sigma(32) gene, indicating that the cognate sigma(32) works more efficiently for the X. campestris promoters.
Weng
S F
SF
Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China. Sfweng@dragon.nchu.edu.tw
Tai
P M
PM
Yang
C H
CH
Wu
C D
CD
Tsai
W J
WJ
Lin
J W
JW
Tseng
Y H
YH
D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D017930:Genes, Reporter; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics; D018869:Heat-Shock Response / Q000235:genetics*; D006358:Hot Temperature; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D016959:Xanthomonas campestris / Q000235:genetics*
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; C068113:GrpE protein, Bacteria; C489400:GrpE protein, E coli; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012097:Repressor Proteins; C063842:dnaK protein, E coli