Tags

Type your tag names separated by a space and hit enter

Thermoregulation of Shigella and Escherichia coli EIEC pathogenicity. A temperature-dependent structural transition of DNA modulates accessibility of virF promoter to transcriptional repressor H-NS.
EMBO J. 1998 Dec 01; 17(23):7033-43.EJ

Abstract

The expression of plasmid-borne virF of Shigella encoding a transcriptional regulator of the AraC family, is required to initiate a cascade of events resulting in activation of several operons encoding invasion functions. H-NS, one of the main nucleoid-associated proteins, controls the temperature-dependent expression of the virulence genes by repressing the in vivo transcription of virF only below a critical temperature (approximately 32 degrees C). This temperature-dependent transcriptional regulation has been reproduced in vitro and the targets of H-NS on the virF promoter were identified as two sites centred around -250 and -1 separated by an intrinsic DNA curvature. H-NS bound cooperatively to these two sites below 32 degrees C, but not at 37 degrees C. DNA supercoiling within the virF promoter region did not influence H-NS binding but was necessary for the H-NS-mediated transcriptional repression. Electrophoretic analysis between 4 and 60 degrees C showed that the virF promoter fragment, comprising the two H-NS sites, undergoes a specific and temperature-dependent conformational transition at approximately 32 degrees C. Our results suggest that this modification of the DNA target may modulate a cooperative interaction between H-NS molecules bound at two distant sites in the virF promoter region and thus represents the physical basis for the H-NS-dependent thermoregulation of virulence gene expression.

Authors+Show Affiliations

Laboratorio di Genetica, Dipartimento di Biologia MCA, Università di Camerino, 62032 Camerino (MC), Italy.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9843508

Citation

Falconi, M, et al. "Thermoregulation of Shigella and Escherichia Coli EIEC Pathogenicity. a Temperature-dependent Structural Transition of DNA Modulates Accessibility of virF Promoter to Transcriptional Repressor H-NS." The EMBO Journal, vol. 17, no. 23, 1998, pp. 7033-43.
Falconi M, Colonna B, Prosseda G, et al. Thermoregulation of Shigella and Escherichia coli EIEC pathogenicity. A temperature-dependent structural transition of DNA modulates accessibility of virF promoter to transcriptional repressor H-NS. EMBO J. 1998;17(23):7033-43.
Falconi, M., Colonna, B., Prosseda, G., Micheli, G., & Gualerzi, C. O. (1998). Thermoregulation of Shigella and Escherichia coli EIEC pathogenicity. A temperature-dependent structural transition of DNA modulates accessibility of virF promoter to transcriptional repressor H-NS. The EMBO Journal, 17(23), 7033-43.
Falconi M, et al. Thermoregulation of Shigella and Escherichia Coli EIEC Pathogenicity. a Temperature-dependent Structural Transition of DNA Modulates Accessibility of virF Promoter to Transcriptional Repressor H-NS. EMBO J. 1998 Dec 1;17(23):7033-43. PubMed PMID: 9843508.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Thermoregulation of Shigella and Escherichia coli EIEC pathogenicity. A temperature-dependent structural transition of DNA modulates accessibility of virF promoter to transcriptional repressor H-NS. AU - Falconi,M, AU - Colonna,B, AU - Prosseda,G, AU - Micheli,G, AU - Gualerzi,C O, PY - 1998/12/8/pubmed PY - 1998/12/8/medline PY - 1998/12/8/entrez SP - 7033 EP - 43 JF - The EMBO journal JO - EMBO J VL - 17 IS - 23 N2 - The expression of plasmid-borne virF of Shigella encoding a transcriptional regulator of the AraC family, is required to initiate a cascade of events resulting in activation of several operons encoding invasion functions. H-NS, one of the main nucleoid-associated proteins, controls the temperature-dependent expression of the virulence genes by repressing the in vivo transcription of virF only below a critical temperature (approximately 32 degrees C). This temperature-dependent transcriptional regulation has been reproduced in vitro and the targets of H-NS on the virF promoter were identified as two sites centred around -250 and -1 separated by an intrinsic DNA curvature. H-NS bound cooperatively to these two sites below 32 degrees C, but not at 37 degrees C. DNA supercoiling within the virF promoter region did not influence H-NS binding but was necessary for the H-NS-mediated transcriptional repression. Electrophoretic analysis between 4 and 60 degrees C showed that the virF promoter fragment, comprising the two H-NS sites, undergoes a specific and temperature-dependent conformational transition at approximately 32 degrees C. Our results suggest that this modification of the DNA target may modulate a cooperative interaction between H-NS molecules bound at two distant sites in the virF promoter region and thus represents the physical basis for the H-NS-dependent thermoregulation of virulence gene expression. SN - 0261-4189 UR - https://www.unboundmedicine.com/medline/citation/9843508/Thermoregulation_of_Shigella_and_Escherichia_coli_EIEC_pathogenicity__A_temperature_dependent_structural_transition_of_DNA_modulates_accessibility_of_virF_promoter_to_transcriptional_repressor_H_NS_ L2 - https://doi.org/10.1093/emboj/17.23.7033 DB - PRIME DP - Unbound Medicine ER -