FIG. 4.

Deletion analysis of PucR-repressed promoters. The upstream sequences and the positions of the upstream fusion points of the pucA′-lacZ fusions are shown (the downstream sequence fusion point is +180), as are the positions of the downstream sequences and the downstream fusion points of the pucR′-lacZ fusions (the upstream sequence fusion point is −123). The PucR box is indicated (boldface indicates a match with the consensus sequence), as is the −35 sequence. A complementary PucR box in the pucR′-lacZ fusions is located in the noncoding strand. Cells containing the various lacZ fusions were grown under nitrogen-limiting conditions (glutamate) either with or without allantoin. nt, nucleotides.