Figure 4

Representative examples of mRNA decay patterns for selected operons from B. cereus ATCC 10897. For each operon, the upper graph displays the coverage at t0 plotted from the start to the end of the operon, while the lower graph shows, for each single nucleotide position, the log2 ratio of the sequence coverage at different time-points following rifampicin addition (red, t2.5, 2.5 minutes; green, t5, 5 minutes; blue, t10, 10 minutes), relative to the sequence coverage at t0. (a) Operons demonstrating examples of 5' to 3' direction of mRNA decay, that is, the sequence coverage for bases near the 5' end of each ORF in the mRNA drops faster than for bases at the 3' end of ORFs. (b) Operons demonstrating examples of 3' to 5' direction of mRNA decay. The seemingly anomalous pattern for the 2.5 minute or 5 minute time-points in the 5' end of the TU_4695703-4696150_R transcript (green graph, leftmost panel) may be due to technical noise. (c) Operons showing various complex types of decay patterns, where specific blocks of the polycistronic mRNA are degraded faster, or show a pattern of faster decay at both 5' and 3' ends relative to other parts of the mRNA.