FIG. 5.

Semiquantitative analysis of the siaD, lipA, mtrC, mtrD, and mtrE transcripts in intracellular meningococci. (A) Total RNAs were extracted from meningococci (strain B1940) after 8 h of infection of HeLa cells (intracellular) or control bacteria grown for 8 h in culture medium (DMEM). The amounts of siaD- and lipA-specific transcripts were determined by real-time RT-PCR. The scheme of the genomic region encoding capsular elements is reported above the panel. (B) Total RNAs were extracted as described above (A). The amounts of mtrC-, mtrD-, and mtrE-specific transcripts were determined by real-time RT-PCR. The genetic map of the mtrCDE operon and the regulatory gene mtrR is reported above the panel. In A and B, levels of lipA-, siaD-, mtrC-, mtrD-, and mtrE-specific transcripts were normalized to rho mRNA levels. Transcript levels in control bacteria are arbitrarily assumed to equal 1. Each real-time RT-PCR experiment was repeated five times (with triplicate samples) using distinct cDNA preparations, and means and standard deviations (bars) were determined. Asterisks mark statistically significant differences in transcript levels between intracellular and control bacteria (P value of <0.05).