FIG. 5.

Patterns of fliX and flgI transcription during the cell cycle. Swarmer cells from cultures of NA1000 containing either pCM9 (fliX::lacZ) or pCM10 (flgI::lacZ) were isolated and allowed to progress synchronously through the cell cycle. At 15-min intervals, a portion of the culture was removed and proteins were pulse-labeled with [³⁵S]Trans-Label. (A) Results of immunoprecipitation of ³⁵S-labeled β-galactosidase from strains carrying either pCM9 (fliX::lacZ) or pCM10 (flgI::lacZ) and of ³⁵S-labeled flagellar filament proteins, followed by electrophoresis on an SDS–10% polyacrylamide gel and autoradiography. The flagellin proteins were monitored as an internal control and indicator for the quality of cell synchrony. Shown are flagellins recovered from cells carrying the flgI::lacZ fusion. Flagellin proteins recovered from the cells carrying the fliX::lacZ fusion gave nearly identical immunoprecipitation and quantification profiles. The cell types present at each time point, monitored microscopically, are represented schematically above the graphs and the autoradiograms. (B) Quantification of the data in panel A with a Molecular Dynamics PhosphorImager, reported as the percentage of maximal expression for each protein. The duration of the cell cycle was approximately 150 min. Filled boxes represent expression of the fliX::lacZ fusion, open boxes represent expression of the flgI::lacZ fusion, and filled circles represent expression of flagellin. The Roman numerals in parentheses indicate the flagellar class for each gene (fliX, flgI) or protein (flagellins) examined.