title: New insights in the role of HtdA in the regulation of R27 conjugation.
abstract: R27 is the prototype of the IncHI group of conjugative plasmids, which are associated with multidrug resistance in several relevant pathogens. The transfer of this plasmid is thermodependent and all transfer-related genes are encoded in six operons (tra operons). Very little is known about the factors involved in the regulation of the R27 conjugation. This report describes transcriptional studies of the six tra operons. Our results indicate that HtdA, encoded in the R27 plasmid, is involved in the transcriptional repression of four tra operons (F, H, AC and Z). Although HtdA plays a pivotal role in the transcriptional regulation of those operons, it does not exert its effect as a classical repressor. The data indicate the existence of a crosstalk between HtdA and other unknown regulatory factors. The HtdA-mediated regulation of conjugation is independent of the R27 H-NS protein.
authors: Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain.
authors: Marta
authors: M
authors: Gibert
authors: Antonio
authors: A
authors: Juárez
authors: Cristina
authors: C
authors: Madrid
authors: Carlos
authors: C
authors: Balsalobre
mesh_terms: D003227:Conjugation, Genetic; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D009876:Operon; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
chemical_list: D029968:Escherichia coli Proteins; C529458:FimG protein, E coli; D036781:Fimbriae Proteins