<p>(A). Semi-quantitative RT-PCR analysis of SMU.1882, SMU.1883, and <i>gyrA</i> for the strains UA159, Δ<i>covR</i> (IBS603) and Δ<i>covR</i> complemented with pIB30 (IBS603/pIB30). The <i>gyrA</i> gene was included as an internal control to ensure that equal amounts of RNA were loaded per lane. Experiments were repeated at least twice with two independent RNA isolations. (B) Quantitative real-time PCR analysis of SMU.1882 transcript in wild type, Δ<i>covR</i> (IBS603) and Δ<i>covR</i> complemented with pIB30 (IBS603/pIB30). The expression of SMU.1882 was normalized to the expression level of <i>gyrA</i> as an internal reference. Relative fold changes in gene expression are represented as histograms with error bars. Each histogram is the mean of four biological replicates. (C) Reporter fusion assay. The putative promoter of SMU.1882 was fused to a promoter-less <i>gusA</i> reporter gene and inserted into the <i>S. mutans</i> UA159 chromosome. Expression driven from the promoters was evaluated by measuring Gus activity. Gus values were measured from at least three independent cultures; mean values with standard deviations are shown.</p
