FLIU AND FLIV - 2 FLAGELLAR GENES ESSENTIAL FOR BIOSYNTHESIS OF SALMONELLA AND ESCHERICHIA-COLI FLAGELLA

The possible functions of two recently described flagellar genes, fliU and fliV, have been examined. Introduction of gene fliC, encoding the bacterial flagellin protein, into a number of flagellin-deficient Sal monella and Escherichia coli strains failed to complement the mutation s in these strains, and the FliC flagellin was accumulated in the bact erial cytoplasm. Complementation with fliU and fliV, which map downstr eam of fliC, restored motility to some of the mutants which became fla gellated. After inactivation of either fliU or fliV, such complementat ion no longer occurred and the flagellin protein accumulated in the cy toplasm, which suggested that both genes are required for the secretio n of flagellin and expression of motility. Expression of these genes f rom high copy number plasmids resulted in the synthesis of exceptional ly long flagella and in detection of the FliV protein on polyacrylamid e gels.