FIG 3.

Copper induces expression of the lit2-copper resistance operon. (A and B) RNA was extracted from E. faecalis TX1342 cells grown with 0, 0.1, or 1.0 mM CuCl₂ (A) and L. monocytogenes CFSAN023459 cells grown with 0 or 1.0 mM CuCl₂ (B) and probed for expression of the indicated genes. Chromosomal genes are indicated by asterisks. (C) RNA was extracted from E. faecalis TX1342 (top) and L. monocytogenes CFSAN023459 (bottom) cells induced with various metal ions and probed for lit2 expression. Estimated transcript lengths are indicated. (D and E) Expression of the indicated target genes was measured by RT-qPCR from E. faecalis TX1342 (D) and L. monocytogenes CFSAN023459 (E) cells grown with 0, 0.1, or 1.0 mM copper. Expression was normalized in each strain against the internal control gene gyrA. The data are shown as the means ± standard deviations of the results of three replicates.