Fig. 4
Levels of selected tRNAs at different growth stages. a Northern blots of selected tRNAs encoded from the MmucT "transcriptional unit" 11 and tRNAIleGAT ["transcriptional unit" 11 located near oriC, 17 corresponds to Ile_GAT_17 and 15 corresponds to Arg_TCG_15, see Fig. 3a; panels, I – III] and the three MaubT tRNACysGCA [Cys_GCA_53, Cys_GCA_32 and Cys_GCA_72, see (a) and Additional file 3: Figure S4c; panels, IV-VI]. The RNA was extracted from stationary and exponential growing cells as described in Methods. M indicates a pUC19/MspI size marker with selected sizes indicated to the left of (I). Lanes 1-3 and 7-8 represent RNA from exponentially grown cells and lanes 4-6 and 9-11 represent RNA from stationary cells. The identities of the detected tRNAs are marked below the images. The boxed insets show the respective blots probed for 5S rRNA as indicated to the left of panel I. The lower panel I inset represents the same blot probed against tRNAArgTCG. b Levels of tRNAs in MmucT and MaubT in stationary phase relative to exponentially growing cells. The bar plot shows a quantification of the Northern blot data shown in Fig. 5a. The amino acid three-letter code and the corresponding anticodon triplet mark the tRNA isoacceptor variants. The numbers on the x-axis corresponds to the numbering in (a), e.g. 17 correspond to Ile_GAT_17 and as indicated. The experiment was performed as outlined in Methods and values represent the mean and errors based on three independent experiments. Statistical significance using Student’s unpaired, two-tailed t-test; *: p< 0.05; **: p < 0.01; ***: p< 0.001