The rulB gene of plasmid pWW0 is a hotspot for the site-specific insertion of integron-like elements found in the chromosomes of environmental Pseudomonas fluorescens group bacteria.
Bottom Line: The rulAB operon of Pseudomonas spp. confers fitness traits on the host and has been suggested to be a hotspot for insertion of mobile elements that carry avirulence genes.Integration into rulB on pWW0 occurred at position 6488 generating a 3 bp direct repeat.Downstream of these resided ORFs of the 'variable side' with structural and sequence similarity to those encoding survival traits on the fitness enhancing plasmid pGRT1 (ILE(FH1) and ILE(FH5)) and the NR-II virulence region of genomic island PAGI-5 (ILE(FH4)).
Affiliation: Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK.Show MeSH
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Mentions: Restriction mapping of plasmids pWW0FH2–6 using the published sequence of pWW0 as a reference (Greated et al., 2002) suggested that as for pWW0FH1, insertion of the ILE in each case was also most likely into the rulAB operon. Based upon the position of ILEFH1 (from pWW0::ILEFH1), insertion into pWW0 at this point would result in an unaltered rulA gene, but with an interruption 123 bp into the rulB gene (herein referred to as rulB'). However, interruption at this point created an alternative ORF [rulB(2)] encoding a predicted protein of 345 aa with a start codon at original position 6440 (Fig. 2). Fine mapping and sequencing of the region in pWW0::ILEFH1 revealed the insertion of ILEFH1 into pWW0 occurred between positions 6488–6490 in the ruvB (rulB) gene generating a target repeat of 5′-GAT-3′ at the insertion site (Fig. 2).
Affiliation: Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK.