Promoter properties and negative regulation of the uvrA gene by the LexA represser and its amino-terminal DNA binding domain

Bertrand-Burggraf, Elisabeth; Hurstel, Serge; Daune, Michel; Schnarr, Manfred

doi:10.1016/0022-2836(87)90220-8

Cited by 74 publications

(41 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Certain other repressors also have binding sites that overlap or lie between the RNA polymerasebinding motifs; they may provide models for MarA action (36,37). LexA sterically blocks the binding of RNA polymerase to the uvrA promoter (38). MerR bends the Ϫ10 motif of the merT promoter away from RNA polymerase, causing a reduction in the rate of open complex formation (39,40).…”

Section: Discussionmentioning

confidence: 99%

The Escherichia coli Transcriptional Regulator MarA Directly Represses Transcription of purA and hdeA

Schneiders

Barbosa

McMurry

et al. 2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

The Escherichia coli MarA protein mediates a response to multiple environmental stresses through the activation or repression in vivo of a large number of chromosomal genes. Transcriptional activation for a number of these genes has been shown to occur via direct interaction of MarA with a 20-bp degenerate asymmetric "marbox" sequence. It was not known whether repression by MarA was also direct. We found that purified MarA was sufficient in vitro to repress transcription of both purA and hdeA. Transcription and electrophoretic mobility shift experiments in vitro using mutant promoters suggested that the marbox involved in the repression overlapped the ؊35 promoter motif and was in the "backward" orientation. This organization contrasts with that of the class II promoters activated by MarA, in which the marbox also overlaps the ؊35 motif but is in the "forward" orientation. We conclude that MarA, a member of the AraC/XylS family, can act directly as a repressor or an activator, depending on the position and orientation of the marbox within a promoter.

show abstract

Section: Discussionmentioning

confidence: 99%

The Escherichia coli Transcriptional Regulator MarA Directly Represses Transcription of purA and hdeA

Schneiders

Barbosa

McMurry

et al. 2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…This mutually exclusive binding of CarA and MxRNAP to their specific sites is consistent with CarA sterically hindering access of MxRNAP to P B . Thus, CarA would belong to the class of transcriptional repressors that includes, among others, the classical paradigms LacI, cI, and LexA repressors (4,53,54), whose operators at least partially overlap the promoter and occlude RNAP on repressor-operator binding.…”

Section: Discussionmentioning

confidence: 99%

Operator Design and Mechanism for CarA Repressor-mediated Down-regulation of the Photoinducible carB Operon in Myxococcus xanthus

Lopez-Rubio

Padmanabhan

Lázaro

et al. 2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

The carB operon encodes all except one of the enzymes involved in light-induced carotenogenesis in Myxococcus xanthus. Expression of its promoter (P B ) is repressed in the dark by sequence-specific DNA binding of CarA to a palindrome (pI) located between positions ؊47 and ؊64 relative to the transcription start site. This promotes subsequent binding of CarA to additional sites that remain to be defined. CarS, produced in the light, interacts physically with CarA, abrogates CarA-DNA binding, and thereby derepresses P B . In this study, we delineate the operator design that exists for CarA by precisely mapping out the second operator element. For this, we examined how stepwise deletions and site-directed mutagenesis in the region between the palindrome and the transcription start site affect CarA binding around P B in vitro and expression of P B in vivo. These revealed the second operator element to be an imperfect interrupted palindrome (pII) spanning positions ؊26 to ؊40. In vitro assays using purified M. xanthus RNA polymerase showed that CarA abolishes P B -RNA polymerase binding and runoff transcription and that both were restored by CarS, thus rationalizing the observations in vivo. CarA binding to pII (after association with pI) effectively occludes RNA polymerase from P B and so provides the operative mechanism for the repression of the carB operon by CarA. The bipartite operator design, whereby transcription is blocked by the low affinity CarA-pII binding and is readily restored by CarS, may have evolved to match the needs for a rapid and an effective response to light.

show abstract

“…As reported previously [3,4,6,16], this technique relies on the production of short oligonucleotides. In our case, using the dinucleotide GpU as starting nucleotide and UTPyANS for elongation, leads to the tetranucleotide GpUpUpU for the uvrA promoter.…”

Section: Abortive Initiation Assaysmentioning

confidence: 99%

“…(iii) Effector (repressors or activators) proteins which are, in some cases, responsible for a major part of the transcription regulation [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…Activation of these genes is obtained during the induction of the SOS system by the cleavage of LexA in the presence of another protein (the activated form of RecA) (reviews [10,11]). Recently, we have followed the initiation of transcription of the uvrA gene, on a linear plasmid, by abortive initiation with a fluorescence assay, as well as its regulation by the LexA repressor [6].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fast abortive initiation of uvrA promoter in a supercoiled plasmid studied by stopped‐flow techniques

et al. 1987

View full text Add to dashboard Cite

In order to follow the fast kinetics of abortive initiation (lag time from 1 ms to l0 s), we have built a stoppedflow apparatus equipped for fluorescence detection. The small volume used for each assay (35 #l), and the short dead time (~ 0.5 ms) are the essential advantages of this apparatus. Supercoiling of DNA affects considerably the initiation of transcription from the uvrA promoter. It decreases the lag time due to the isomerisation process 3-fold. Nevertheless, it does not change significantly the product gBk2, which is indicative of promoter strength and shows that uvrA is an 'association-limited' promoter. The presence of the LexA repressor increases the lag time considerably. At least for small RNA polymerase concentrations this increase is stronger for supercoiled than for linearized DNA.

show abstract

Promoter properties and negative regulation of the uvrA gene by the LexA represser and its amino-terminal DNA binding domain

Cited by 74 publications

References 29 publications

The Escherichia coli Transcriptional Regulator MarA Directly Represses Transcription of purA and hdeA

The Escherichia coli Transcriptional Regulator MarA Directly Represses Transcription of purA and hdeA

Operator Design and Mechanism for CarA Repressor-mediated Down-regulation of the Photoinducible carB Operon in Myxococcus xanthus

Fast abortive initiation of uvrA promoter in a supercoiled plasmid studied by stopped‐flow techniques

Contact Info

Product

Resources

About