The dnaKJ operon of Agrobacterium tumefaciens: Transcriptional analysis and evidence for a new heat shock promoter

G. Segal, E. Z. Ron*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The dnaKJ operon of Agrobacterium tumefaciens was cloned and sequenced and was found to be highly homologous to previously analyzed dnaKJ operons. Transcription of this operon in A. tumefaciens was stimulated by heat shock as well as by exposure to ethanol and hydrogen peroxide. There were two transcripts representing the dnaKJ operon: one containing the dnaK and dnaJ genes and the second containing only the dnaK gene. Primer extension analysis indicated that transcription started from the same site in heat-shocked cells and in untreated cells. The upstream regulatory region of the dnaKJ operon of A. tumefaciens does not contain the highly conserved inverted repeat sequence previously found in the groESL operon of this bacterium, as well as in many other groE and dnaK operons. Sequence analysis of the promoter region of several groESL and dnaK operons from α-purple proteobacteria indicates the existence of a putative promoter sequence different from the known consensus promoter sequences recognized by the Escherichia coli vegetative or heat shock sigma factor. This promoter may constitute the heat shock promoter of these α-purple proteobacteria.

Original languageEnglish
Pages (from-to)5952-5958
Number of pages7
JournalJournal of Bacteriology
Volume177
Issue number20
DOIs
StatePublished - 1995

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