FIG. 1.

Primer extension analysis of five selected genes. There were 10 operons for which the RT-PCR data were inconsistent with the microarray ones (see Table 1). Five (YPO0164, fepB, ysuE, fcuA, and fhuC) of them were chosen for primer extension analysis. RNA was isolated from the WT strain or the fur mutant grown in the presence (−) or absence (+) of iron. By using an oligonucleotide primer complementary to RNA transcript, cDNA was synthesized from the RNA templates. Electrophoresis of primer extension products was performed with a 6% polyacrylamide-8 M urea gel. Lanes C, T, A, and G represent the Sanger sequencing reactions. The transcriptional start sites were underlined.