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Titolo:
Autoactivation and environmental regulation of bfpT expression, the gene coding for the transcriptional activator of bfpA in enteropathogenic Escherichia coli
Autore:
Martinez-Laguna, Y; Calva, E; Puente, JL;
Indirizzi:
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Mol Microbiol, Cuernavaca 62250, Morelos, Mexico Univ Nacl Autonoma Mexico Cuernavaca Morelos Mexico62250 Morelos, Mexico
Titolo Testata:
MOLECULAR MICROBIOLOGY
fascicolo: 1, volume: 33, anno: 1999,
pagine: 153 - 166
SICI:
0950-382X(199907)33:1<153:AAEROB>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
HOST EPITHELIAL-CELLS; BUNDLE-FORMING PILUS; PROTEIN TRANSLOCATION; SIGNAL-TRANSDUCTION; VIBRIO-CHOLERAE; ADHERENCE; PROMOTERS; CLONING; OPERON; EPEC;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Puente, JL Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Mol Microbiol, Apdo Postal510-3, Cuernavaca 62250, Morelos, Mexico Univ Nacl Autonoma Mexico Apdo Postal 510-3 Cuernavaca Morelos Mexico 62250
Citazione:
Y. Martinez-Laguna et al., "Autoactivation and environmental regulation of bfpT expression, the gene coding for the transcriptional activator of bfpA in enteropathogenic Escherichia coli", MOL MICROB, 33(1), 1999, pp. 153-166

Abstract

Expression of bfpA, the gene coding for the structural subunit of the bundle-forming pili (BFP) in enteropathogenic Escherichia coli(EPEC), requires the product of bfpT(also called perA), a member of the AraC family of transcriptional regulators. Here, we show that bfpT-cat fusions were not expressed in a bfpT(-) or in a non-EPEC strain, unless a functional bfpT was present, indicating that an autoregulatory mechanism is involved in expression. Further experiments with bfpT-cat fusions and primer extension analysis showed that bfpT is transcribed from a conventional sigma-70 promoter and thatit is expressed throughout the growth curve. It is regulated in response to the ammonium concentration, temperature and growth media, in the same proportions as those described previously for bfpA. In addition, bfpT and bfpAexpression was also modulated by osmolarity, but was not affected by pH, iron excess or limitation. Deletion analysis of the bfpT upstream region revealed that a DNA segment of 81 bp, extending upstream from the transcriptional start site, contained all the sequence elements required for maximal expression of bfpT. Furthermore, it shares significant homology with a bfpA upstream AT-rich region, which has been shown to be involved in the BfpT-dependent regulation of bfpA. Interestingly, ammonium repression was observed only when bfpT-cat or bfpA-cat expression was complemented in an EPEC background, whereas low-temperature regulation was observed in both EPEC and non-EPEC strains. This suggests that specific regulatory elements are present in EPEC, while others are shared with non-pathogenic E. coli.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 12/07/20 alle ore 01:32:45