Host cell killing and bacterial conjugation require overlapping sets of genes within a 22-kb region of the Legionella pneumophila genome

摘要: A 22-kb DNA locus of Legionella pneumophila is described that contains 18 genes, 16 which are required for macrophage killing (icm genes). In this paper two previ- ously icm loci were linked by the discovery five genes located between loci. Four newly (icmMLKE) and one dispensable. The appeared to be organized as six individual (icmR, icmQ, icmG, icmC, icmD, icmF), four operons (icmTS, icmPO, icmMLKE, icmJB). (icmP, icmO, icmL, icmE) show significant sequence similarity plasmid involved in conjugation, whereas other found not bear any database entries. We L. can mediate transfer at a frequency 10 23 24 per donor. Strains containing null mutations (icmT icmR) showed severe reduction conjugation killing. an insertion (icmF, icmE, dotA) shown have less defect conjugation. Mutations 11 had no effect on frequency. currently do know whether itself plays role It possible either small plasmids take advantage existing secretion system mobilized or human pneumophila.