Inhibition of RNase III cleavage of <i>betT</i> mRNA by introducing a mutation at the cleavage site.

<p>(A) Secondary structures of the hairpin encompassing RNase III cleavage sites. Nucleotide substitutions (C33U and C39U) at the RNase III cleavage sites are indicated. (B) Effects of a nucleotide substitution at the cleavage sites on RNase III activity on <i>betT</i> mRNA. Primer extension experiments were performed as described in the legend to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100520#pone-0100520-g002" target="_blank">Figure 2B</a>. (C) Effects of an RNase III cleavage site mutation on steady-state levels of <i>betT</i> mRNA determined by semi-quantitative RT-PCR analysis. Total RNA was prepared from strains MG1655<i>rncbetT</i> harboring pRNC1 and either pBetRS1 or its derivative (pBetRS1-C33U or pBetRS1-C39U), which were grown in LB at 37°C to an OD₆₀₀ of 0.6.