J. Biol. Chem., Vol. 266, Issue 17, 10830-10838, Jun, 1991

In vivo interactions of the NahR transcriptional activator with its target sequences. Inducer-mediated changes resulting in transcription activation

JZ Huang and MA Schell
Department of Microbiology, University of Georgia, Athens 30602.

The nahR gene from the NAH7 naphthalene degradation plasmid encodes a LysR-type transcriptional activator of the nah and sal promoters (Pnah and Psal, respectively) that responds to the inducer salicylate. In vivo methylation protection experiments with dimethyl sulfate showed that in the absence of inducer, NahR interacts in a similar manner with its target sites at Psal and Pnah. Both target sites also have very similar sequences comprised of a 4-base pair interrupted dyad containing two symmetrical guanines (-73 and -64 of Pnah; -71 and -62 of Psal), each located in adjacent major grooves on the same helical face, and both strongly protected by NahR. When inducer was present, several additional guanines of Pnah (-35, -45, and -58) and Psal (-42 and -40) became protected from methylation, while a guanine at -52 of Pnah became markedly enhanced for methylation, indicating that inducer and NahR-dependent interactions with these downstream sites of each promoter are quite different. Deletion of Psal sequences downstream of - 30 did not affect its methylation patterns suggesting that NahR alone is responsible for the altered reactivities of these nucleotides. Similar in vivo methylation analyses with inducer-insensitive or inducer-independent NahR mutants also suggested that all alterations in methylation sensitivity are directly caused by NahR. It is more probable that the salicylate-induced reactivity changes result from direct NahR-guanine contacts which are required for, but not sufficient for transcription activation; however, they could also result from NahR- induced DNA contortions caused by upstream protein-DNA contacts.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				H. Fujihara, H. Yoshida, T. Matsunaga, M. Goto, and K. Furukawa Cross-Regulation of Biphenyl- and Salicylate-Catabolic Genes by Two Regulatory Systems in Pseudomonas pseudoalcaligenes KF707 J. Bacteriol., July 1, 2006; 188(13): 4690 - 4697. [Abstract] [Full Text] [PDF]

				N. Golic, M. Schliekelmann, M. Fernandez, M. Kleerebezem, and R. van Kranenburg Molecular characterization of the CmbR activator-binding site in the metC-cysK promoter region in Lactococcus lactis Microbiology, February 1, 2005; 151(2): 439 - 446. [Abstract] [Full Text] [PDF]

				M. Dai and S. D. Copley Genome Shuffling Improves Degradation of the Anthropogenic Pesticide Pentachlorophenol by Sphingobium chlorophenolicum ATCC 39723 Appl. Envir. Microbiol., April 1, 2004; 70(4): 2391 - 2397. [Abstract] [Full Text] [PDF]

				R. M. Jones, B. Britt-Compton, and P. A. Williams The Naphthalene Catabolic (nag) Genes of Ralstonia sp. Strain U2 Are an Operon That Is Regulated by NagR, a LysR-Type Transcriptional Regulator J. Bacteriol., October 1, 2003; 185(19): 5847 - 5853. [Abstract] [Full Text] [PDF]

				D. J. Lessner, R. E. Parales, S. Narayan, and D. T. Gibson Expression of the Nitroarene Dioxygenase Genes in Comamonas sp. Strain JS765 and Acidovorax sp. Strain JS42 Is Induced by Multiple Aromatic Compounds J. Bacteriol., July 1, 2003; 185(13): 3895 - 3904. [Abstract] [Full Text] [PDF]

				T. Watanabe, H. Fujihara, and K. Furukawa Characterization of the Second LysR-Type Regulator in the Biphenyl-Catabolic Gene Cluster of Pseudomonas pseudoalcaligenes KF707 J. Bacteriol., June 15, 2003; 185(12): 3575 - 3582. [Abstract] [Full Text] [PDF]

				G. van Keulen, A. N. J. A. Ridder, L. Dijkhuizen, and W. G. Meijer Analysis of DNA Binding and Transcriptional Activation by the LysR-Type Transcriptional Regulator CbbR of Xanthobacter flavus J. Bacteriol., February 15, 2003; 185(4): 1245 - 1252. [Abstract] [Full Text] [PDF]

				W. Park, P. Padmanabhan, S. Padmanabhan, G. J. Zylstra, and E. L. Madsen nahR, encoding a LysR-type transcriptional regulator, is highly conserved among naphthalene-degrading bacteria isolated from a coal tar waste-contaminated site and in extracted community DNA Microbiology, August 1, 2002; 148(8): 2319 - 2329. [Abstract] [Full Text] [PDF]

				A. Cebolla, C. Sousa, and V. d. Lorenzo Rational design of a bacterial transcriptional cascade for amplifying gene expression capacity Nucleic Acids Res., February 1, 2001; 29(3): 759 - 766. [Abstract] [Full Text] [PDF]

				C. Jørgensen and G. Dandanell Isolation and Characterization of Mutations in the Escherichia coli Regulatory Protein XapR J. Bacteriol., July 15, 1999; 181(14): 4397 - 4403. [Abstract] [Full Text]

				A. Cebolla, C. Sousa, and V. de Lorenzo Effector Specificity Mutants of the Transcriptional Activator NahR of Naphthalene Degrading Pseudomonas Define Protein Sites Involved in Binding of Aromatic Inducers J. Biol. Chem., February 14, 1997; 272(7): 3986 - 3992. [Abstract] [Full Text] [PDF]