LOSS OF FLAGELLATION IN DNAA MUTANTS OF ESCHERICHIA-COLI

A dnaA46 mutant of Escherichia coli showed loss of motility at 37 degr ees C, a permissive temperature for cell growth of this mutant. Other dnaA mutations near the middle of the gene also caused an immotile phe notype. The amount of flagellin was much less in the dnaA46 mutant tha n in the wild-type control, as was the promoter activity. DnaA protein may play an important role in expression of the fliC gene.