Fig. 2.

Hierarchical expression of flagella genes. Dynamics of expression of class 1, class 2, and class 3 genes in flagella regulatory network in wild-type S. typhimurium. Characteristic of the expression pattern is the delay in induction of class 3. This delay corresponds to the time required by the bacterium to assemble a sufficient number of HBBs to relieve FlgM repression of FliA. The class 1 product in the graph represents the free FlhD₄C₂ present in the cell, and does not include the FlhD₄C₂ bound with FliT. Class 2 proteins represent the HBB proteins lumped together. Class 3 proteins represent the filament, chemotaxis, and motor proteins