FIG. 1.

Genetic organization of AF/R1 determinants and constructs utilized in complementation and adherence experiments. Boxes indicate peptides encoded by pRKB15. The thick lines on the sides of the boxes indicate the presence and positions of signal peptides. Arrows above the boxes indicate directions of transcription. The numbers in the boxes are the predicted molecular masses (in kilodaltons) of the mature polypeptides. Sites of transposon insertions in pRKB18 are indicated as follows: Tn5 insertions not affecting the expression of AF/R1 pili (white triangles) and Tn5 insertions which abolished the expression of AF/R1 pili (black triangles). All transposon mutagenesis was performed on pRKB18. p598 is described in Materials and Methods. Its construction required mutagenesis to insert an SphI site in the carboxy-terminal end of afrS. The new site allowed the subcloning of an SphI-KpnI fragment that expressed AfrR.