FIG. 1.

Regulation of the N. meningitidis rpsE, rpmD, rplO, and secY genes under iron-depleted and iron-replete conditions. (A) Schematic representation of the N. meningitidis MC58 secY gene and genes encoding ribosomal proteins within the spc operon. ORFs within the spc operon are labeled and encode genes for 10 ribosomal proteins [RplN (L14), RplX (L24), RplE (L5), RpsN (S14), RpsH (S8), RplF (L6), RplR (L18), RpsE (S5), RpmD (L30), and RplO (L15)], SecY, and a translation initiation factor (IF-1). The promoter region of the operon is represented as “P,” and the direction of transcription is represented with an arrow, as previously described for the E. coli spc operon (3). The ORFs represented are not drawn to scale. (B) Schematic representation of the DNA fragments amplified during transcription and cotranscription analysis. Each ORF examined in this study is labeled with the corresponding gene; regions amplified are represented with double-headed arrows, and the size of each amplicon is given for each arrow. A previously identified Fur binding sequence in the upstream region of the secY gene (17) is represented by double asterisks (**). (C and D) Transcription (C) and cotranscription (D) analyses of the rpsE, rpmD, rplO, and secY genes. Cultures of N. meningitidis were grown in CDM broth under iron-depleted (−) (12.5 μM desferal) or iron-replete (+) (100 μM ferric nitrate) conditions, and samples were removed at 4 h for RNA preparation. Approximately 250 ng of total RNA was used in each in RT-PCR and was amplified with the primers listed in Table 1.