Abstract
Expression of the 987P gene cluster is activated by the adjacent IS 1 element of an STpa transposon. Nucleotide sequence analysis of the 987P-DNA region contiguous with this IS 1 element revealed the presence of an open reading frame designated fapR, encoding a basic protein of 260 amino acid residues with a molecular mass of 30,349 Daltons. The gene product, FapR, possesses similarity to a number of positive regulators of gene expression: VirF, Rns, AppY and EnvY. Moreover, a 43-amino-acid residue sequence in the C-terminal part of FapR is similar to the C-terminal domain of AraC, RhaR, and RhaS. Expression of fapR is dependent on the adjacent IS 1 element. The FapR protein appears to be required for activation of the silent promoter of the fimbrial subunit gene, fapC.