title: Global transcriptional regulator KorC coordinates expression of three backbone modules of the broad-host-range RA3 plasmid from IncU incompatibility group.
abstract: The broad-host-range conjugative RA3 plasmid from IncU incompatibility group has been isolated from the fish pathogen Aeromonas hydrophila. DNA sequencing has revealed a mosaic modular structure of RA3 with the stabilization module showing some similarity to IncP-1 genes and the conjugative transfer module highly similar to that from PromA plasmids. The integrity of the mosaic plasmid genome seems to be specified by its regulatory network. In this paper the transcriptional regulator KorC was analyzed. KorCRA3 (98 amino acids) is encoded in the stabilization region and represses four strong promoters by binding to a conserved palindrome sequence, designated OC on the basis of homology to the KorC operator sequences in IncP-1 plasmids. Two of the KorCRA3-regulated promoters precede the first two cistrons in the stabilization module, one fires towards replication module, remaining one controls a tricistronic operon, whose products are involved in the conjugative transfer process. Despite the similarity between the binding sites in IncU and IncP-1 plasmids, no cross-reactivity between their KorC proteins has been detected. KorC emerges as a global regulator of RA3, coordinating all its backbone functions: replication, stable maintenance and conjugative transfer.
authors.affiliation: Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics, PAS, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Ludwiczak
authors.forename: P
authors.initials: P
authors.lastname: Dolowy
authors.forename: A
authors.initials: A
authors.lastname: Markowska
authors.forename: J
authors.initials: J
authors.lastname: Szarlak
authors.forename: A
authors.initials: A
authors.lastname: Kulinska
authors.forename: G
authors.initials: G
authors.lastname: Jagura-Burdzy
mesh_terms: D016980:Aeromonas hydrophila / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003227:Conjugation, Genetic; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D058507:Host Specificity; D008969:Molecular Sequence Data; D009876:Operon; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012097:Repressor Proteins