ANALYSIS OF THE LEGIONELLA-PNEUMOPHILA FLII GENE - INTRACELLULAR GROWTH OF A DEFINED MUTANT DEFECTIVE FOR FLAGELLUM BIOSYNTHESIS

Using a PCR-based strategy and degenerate oligonucleotides, we isolate d a Legionella pneumophila gene that showed high sequence similarity t o members of the fliI gene family. An insertion mutation that disrupte d the fliI open reading frame was recombined onto the L. pneumophila c hromosome and analyzed for its effects on production of flagella and i ntracellular growth. The mutation resulted in loss of surface-localize d flagellin protein but had no effect on the ability of the bacteria t o grow within cultured cells. Therefore, in spite of the fact that som e aflagellar mutations render L. pneumophila unable to grow within mac rophages, the isolation of this defined mutant confirms that productio n of flagella is not required for intracellular growth.