ИСТИНА

DNA secondary structures play an important role in various processes of genome functioning from bacteria to human. A stem-loop structure is an elementary structural motif that can function as terminator, attenuator, promoter and recognition elements. Earlier we annotated bacterial genomes with stem-loop structures and found that promoter regions of transcription factors (TF) are enriched with stem-loops. Here we posed a question whether stem-loops can play a role in TF autoregulation. To test this hypothesis we applied an evolutionary algorithm selecting statistically significant stem-loop structures in the TF promoter regions. For the directed selection we used the Pearson's chi-squared test – the greater the test value, the better the stem-loop parameters. For autoregulated TFs the evolutionary algorithm found the set of parameters so that the selected type of stem-loops was found in the promoter regions of the TFs with the feedback loop, and other TFs did not have any stem-loop structures. These results support the hypothesis of a possible regulatory role of stem-loops in the TF promoter regions.