Cloning and expression in Escherichia coli of the dnaK gene of Zymomonas mobilis

Michel, Gérard

doi:10.1128/jb.175.10.3228-3231.1993

Cited by 22 publications

(12 citation statements)

References 27 publications

(26 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A lac fusion of the dnaK operon from Z. mobilis was thermoregulated in E. coli (24), and the dnaK operon of Brucella ovis was expressed in a heat shock-dependent manner in E. coli (8). These two dnaK operons do not contain the IR found in the groESL operons of alpha purple proteobacteria.…”

Section: Vol 178 1996 Regulation Of the A Tumefaciens Groesl Operomentioning

confidence: 99%

Heat shock activation of the groESL operon of Agrobacterium tumefaciens and the regulatory roles of the inverted repeat

Segal

Ron

1996

J Bacteriol

View full text Add to dashboard Cite

Deletions were constructed in the conserved inverted repeat (IR) found in the groESL operon of Agrobacterium tumefaciens and in many other groE and dnaK operons and genes in eubacteria. These deletions affected the level of expression of the operon and the magnitude of its heat shock activation. The IR seems to operate at the DNA level, probably as an operator site that binds a repressor under non-heat shock conditions. The IR was also found to function at the mRNA level, since under non-heat shock conditions transcripts containing deletions of one side of the IR had longer half-lives than did transcripts containing the wild-type IR. Under heat shock conditions, the half-life of the mRNA was unaffected by this deletion because of heat shockdependent cleavage. However, the groESL operon was found to be heat shock activated even after most of the IR was deleted. This observation, together with the fact that the groESL operon of A. tumefaciens was heat shock activated in Escherichia coli and vice versa, suggests that a heat shock promoter regulates the heat shock activation of this operon. The primary role of the IR appears to be in reducing the MRNA levels from this promoter under non-heat shock conditions.The heat shock response is a widespread phenomenon found in all living cells examined (10). It is characterized by the induction of several proteins, some of which are highly conserved in evolution, especially those encoded by the groEL (hsp60) and the dnaK (hsp70) genes (4,16,17,48).One of the recent findings concerning the groE and dnaK operons of many eubacteria is the existence of an inverted repeat (IR) (TTAGCACTC-N 9 -GAGTGCTAA) located in the upstream regulatory region. This IR has been found in a large number of phylogenetically distant bacteria (1,2,5,9,13,20,21,25,27,28,30,33,34,39,41,42) and is highly conserved. So far, this IR has been found only in the upstream regions of groE and dnaK operons or genes, except for two cases in which it is located upstream of the dnaJ gene (14, 39). In these two cases, the dnaJ gene is separated from the dnaK gene, while generally they are organized in the same operon.The role of the IR in heat shock induction was characterized in two low-GC gram-positive bacteria, Lactococcus lactis (39) and Bacillus subtilis (46,49). In the dnaJ gene of L. lactis, deletion of the IR resulted in the loss of heat shock activation of this gene. In addition, the transcription level at low temperatures was higher without the IR, in comparison to that of the wild-type gene. In the dnaK operon of B. subtilis, site-directed mutagenesis of the IR resulted in a high level of transcription at low temperatures and a reduction in heat shock activation. In B. subtilis, the protein encoded by orf39 (the first gene in the dnaK operon of B. subtilis) was found to serve as the repressor and to bind the IR at the DNA level (45). In the groE operon of B. subtilis, the IR was also shown to function as an operator site and to be involved in determining the half-life of the transcript to which it is conn...

show abstract

Section: Vol 178 1996 Regulation Of the A Tumefaciens Groesl Operomentioning

confidence: 99%

Heat shock activation of the groESL operon of Agrobacterium tumefaciens and the regulatory roles of the inverted repeat

Segal

Ron

1996

J Bacteriol

View full text Add to dashboard Cite

show abstract

“…A lacZ fusion of the dnaK operon from Zymomonas mobilis was thermoregulated in E. coli (26), and the dnaK operon of B. ovis was expressed in a heat shock-dependent manner in E. coli (9). In both cases, the transcription start site of the operon was not determined, and there is no evidence that transcription in E. coli occurred from the same promoter as that in the original bacteria.…”

mentioning

confidence: 99%

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

Segal

Ron

1995

J Bacteriol

View full text Add to dashboard Cite

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 ␣-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 ␣-purple proteobacteria.The heat shock response is a widespread phenomenon that was found in all living cells examined (11). It is characterized by the induction of several proteins, some of which are highly conserved in evolution, especially those encoded by the groEL (hsp60) and dnaK (hsp70) genes (5, 14, 53). Several of the heat shock proteins are also induced by other stress conditions such as exposure to ethanol, heavy metals, and hydrogen peroxide (30,34,45).In Escherichia coli the heat shock response is mediated by the positive regulator protein sigma-32. This sigma factor recognizes a promoter sequence different from that of the vegetative sigma factor (sigma-70) and in this way specifically transcribes heat shock genes (7, 52).Recently, it was observed that gram-positive bacteria and several gram-negative bacteria contain a highly conserved inverted repeat sequence in the upstream regulatory region of groESL and dnaK operons (1, 6, 10, 15, 21, 27-29, 31, 32, 38, 40, 44, 47, 48). In Bacillus subtilis (54) and Lactococcus lactis (44), it was shown that this inverted repeat is involved in the heat shock response and that these heat shock operons contain a promoter sequence recognized by the vegetative sigma factor. In B. subtilis, other heat shock-activated genes contain a promoter sequence recognized by the SigB sigma factor, which is known as a general stress factor (49).In a previous paper (40), we showed that the groESL operon of Agrobacterium tumefaciens contains the highly conserved inverted repeat sequence and that the operon is heat shock activated. Here, we present results from the cloning and sequencing of the dnaKJ operon of A. tumefaciens. The operon was shown to be heat shock activated, although it does not contain the inverted repeat sequence found in the groESL operon of this bacterium. The results presented in this paper and sequence analysis of heat shock promoters from o...

show abstract

“…Some bacteria simultaneously use more than one strategy to ensure the well-adjusted production of heat shock proteins under harsh conditions. For example, heat shock regulation processes mediated by CIRCE and 32 coexist in some bacteria, including Agrobacterium tumefaciens, Bordetella pertussis, Caulobacter crescentus, and Zymomonas mobilis (2,3,20,39,40,45,46,50,51). Dual heat shock regulation by HrcA and CtsR has been demonstrated for the Staphylococcus aureus dnaK and groESL operons and for the Streptococcus salivarius clpP gene (10,11).…”

mentioning

confidence: 99%

CtsR Is the Master Regulator of Stress Response Gene Expression inOenococcus oeni

et al. 2005

View full text Add to dashboard Cite

Cloning and expression in Escherichia coli of the dnaK gene of Zymomonas mobilis

Cited by 22 publications

References 27 publications

Heat shock activation of the groESL operon of Agrobacterium tumefaciens and the regulatory roles of the inverted repeat

Heat shock activation of the groESL operon of Agrobacterium tumefaciens and the regulatory roles of the inverted repeat

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

CtsR Is the Master Regulator of Stress Response Gene Expression inOenococcus oeni

Contact Info

Product

Resources

About