Fig. 1.

GlnR directly regulates transcription of acuA, which encodes a protein acetyltransferase in S. erythraea. (A) Genetic organization of the acuA gene of S. erythraea and its putative GlnR-binding site. The predicted transcription start site (TSS) is shown. (B) EMSAs of purified His–GlnR binding toward the predicted motifs. The DNA probes (P_acuA) containing the predicted motifs were incubated with GlnR and a 200-fold excess of nonspecific competitor DNA (sperm DNA). (C) Transcriptional analysis of acuA gene response to nitrogen availability (N^XS, excess nitrogen; N^L, low nitrogen) in S. erythraea WT and glnR-deleted mutant (ΔglnR) strains. (D) Analysis of acuA transcription in S. erythraea WT, ΔglnR mutant, and glnR complementary (ΔglnR::glnR) strains. Error bars show the SD from three independent experiments.