This might also indicate that this unknown function

could be under the control of the FljA protein. It is tempting to speculate that a site-directed integration event also occurred in the case of the yjjY mutants. An IS30-based site-directed integration system could be utilized in several ways, for example to search for and to tag the targets of DNA-binding Ixazomib clinical trial proteins in vivo. The IS30 transposase has a number of features that make the further development of the IS30-based site-directed integration system as a tool for functional genomics worthwhile. These advantages include the high activity of the (IS30)2 intermediate structure (Olasz et al., 1993; Kiss & Olasz, 1999; Table S1), the lack of size limitations (high-molecular-weight plasmids can be integrated as well – unpublished data), the integrated product is stable in the absence of the IS30 transposase because IS30 is not present in the vast majority of bacteria and IS30 is active both in bacteria and in eukaryotes (Szabo et al., 2003). PLX-4720 clinical trial Fusion of the IS30 transposase with transcription factors, repressors, DNA methylases or with any other kind of DNA-binding proteins

may establish a vast array of potential integration sites. A further advantage of this mutagenesis system is that it might be useful in such cases when the sequence of the target gene is not known (e.g. new isolates of pathogenic bacteria), and the traditional molecular methods (e.g. Datsenko & Wanner, 2000) cannot be applied. In such a situation, the adaptation of this technique is more promising. Because of the absence of flagellae, the lack of antiflagellar

antibodies can be used as a negative marker in the serological differentiation of vaccinated chicks from those infected by wild strains of S. Enteritidis (Adriaensen et al., 2007). It is believed that nonmotile mutants produced by our site-directed mutagenesis method could also aid the development of a negatively marked vaccine against S. Enteritidis infection of chicks. This study was supported by the Hungarian Grant NKFP 4/040/2001 and in part by the EU FP6 SUPASALVAC and CRAB (LSH-2004-2.1.2-4) Program. RANTES We thank M. Szabó, J. Kiss and Z. Nagy for their helpful advice and fruitful discussions on molecular techniques. We also thank I. Könczöl, E. Keresztúri and M. Turai for their skilful help with the bacterial techniques. Fig. S1. Determination of yjjY insertions by PCR amplification. Table S1. Transposition frequency of the pFOL1069 integration donor in the Salmonella Enteritidis 11 recipient strain mediated by the wt and the IS30–FljA fusion protein. Please note: Wiley-Blackwell is not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article.