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: Here, for the first time, we show that rulB on plasmid pWW0 is a hotspot for the active site-specific integration of related integron-like elements (ILEs) found in six environmental pseudomonads (strains FH1-FH6).Integration into rulB on pWW0 occurred at position 6488 generating a 3 bp direct repeat.Collectively, these ILEs share features with the previously described type III protein secretion system effector ILEs and are considered important to host survival and transfer of fitness enhancing and (a)virulence genes between bacteria.
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.