Flavobacterium johnsoniaeGliding Motility Genes Identified bymarinerMutagenesis

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Abstract
Cells ofFlavobacterium johnsoniaeglide rapidly over surfaces. The mechanism ofF. johnsoniaegliding motility is not known. Eightgldgenes required for gliding motility have been described. Disruption of any of these genes results in complete loss of gliding motility, deficiency in chitin utilization, and resistance to bacteriophages that infect wild-type cells. Two modifiedmarinertransposons,HimarEm1andHimarEm2, were constructed to allow the identification of additional motility genes.HimarEm1andHimarEm2each transposed inF. johnsoniae, and nonmotile mutants were identified and analyzed. Four novel motility genes,gldK, gldL, gldM, andgldN, were identified. GldK is similar in sequence to the lipoprotein GldJ, which is required for gliding. GldL, GldM, and GldN are not similar in sequence to proteins of known function. Cells with mutations ingldK, gldL, gldM, andgldNwere defective in motility and chitin utilization and were resistant to bacteriophages that infect wild-type cells. Introduction ofgldA, gldB, gldD, gldFG, gldH, gldI, andgldJand the region spanninggldK, gldL, gldM, andgldNindividually into 50 spontaneous and chemically induced nonmotile mutants restored motility to each of them, suggesting that few additionalF. johnsoniae gldgenes remain to be identified.