Global transcriptional regulation of backbone genes in broad-host-range plasmid ra3 from the incu group involves segregation protein korb (parb family)

Anna Kulińska , Jolanta Godziszewska , Anna Wojciechowska , Marta Ludwiczak , Grażyna Jagura-Burdzy


The KorB protein of the broad-host-range conjugative plasmid RA3 from the IncU group belongs to the ParB family of plasmid and chromosomal segregation proteins. As a partitioning DNA-binding factor, KorB specifically recognizes a 16-bp palindrome which is an essential motif in the centromere-like sequence parSRA3, forms a segrosome, and together with its partner IncC (ParA family) participates in active DNA segregation ensuring stable plasmid maintenance. Here we show that by binding to this palindromic sequence, KorB also acts as a repressor for the adjacent mobC promoter driving expression of the mobC-nic operon, which is involved in DNA processing during conjugation. Three other promoters, one buried in the conjugative transfer module and two divergent promoters located at the border between the replication and stability regions, are regulated by KorB binding to additional KorB operators (OBs). KorB acts as a repressor at a distance, binding to OBs separated from their cognate promoters by between 46 and 1,317 nucleotides. This repressor activity is facilitated by KorB spreading along DNA, since a polymerization-deficient KorB variant with its dimerization and DNA-binding abilities intact is inactive in transcriptional repression. KorB may act as a global regulator of RA3 plasmid functions in Escherichia coli, since its overexpression in trans negatively interferes with mini-RA3 replication and stable maintenance of RA3.
Author Anna Kulińska (FC / IBC / DDTB)
Anna Kulińska,,
- Department Of Drug Technology And Biotechnology
, Jolanta Godziszewska
Jolanta Godziszewska,,
, Anna Wojciechowska (FC / IBC / DDTB)
Anna Wojciechowska,,
- Department Of Drug Technology And Biotechnology
, Marta Ludwiczak
Marta Ludwiczak,,
, Grażyna Jagura-Burdzy
Grażyna Jagura-Burdzy,,
Journal seriesApplied and Environmental Microbiology, ISSN 0099-2240
Issue year2016
Publication size in sheets0.75
Languageen angielski
zam2320.pdf 1.97 MB
Score (nominal)40
ScoreMinisterial score = 40.0, 28-11-2017, ArticleFromJournal
Ministerial score (2013-2016) = 40.0, 28-11-2017, ArticleFromJournal
Publication indicators WoS Impact Factor: 2016 = 3.807 (2) - 2016=4.282 (5)
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