Correlation between IRS and 5′-UTR length. (a) distribution of the 5′-UTR length of different prokaryotes: P. profundum (purple), Helicobacter pilory (green), Caulobacter crescentus (orange), Synechococcus elongatus PCC 7942 (black), Halobacterium salinarum (red) and Sulfolobus solfataricus (blue). (b) Distribution of the IRs length determined on the same six species. In (b) only IRs separating different operons were considered. (c) Median length of all the 5′-UTRs reported in (a) and of IRs reported in (b) is compared and interpolated. (d) UTR length is correlated to intergenic region size (IRS) size in P. profundum. IRs were classified in 11 classes according to their length and separated in four groups considering strand of the adjacent genes: double-regulatory regions, localized between two divergently transcribed genes (−+), single-regulatory (++) (− −) and non-regulatory (+−). “+” refers to forward strand and “–” to reverse strand. UTR length is correlated to IRS. Due to the very low number of (+−) IRs belonging to classes “501-600” and “> 600” these points were not plotted in (d).
Campanaro et al. BMC Genomics 2012 13:567 doi:10.1186/1471-2164-13-567