Instituto de Agrobiotecnología (IdAB), CSIC-UPNA-Gobierno de Navarra, 31192-Mutilva, Navarra, Spain.
European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SD, UK.
Nucleic Acids Res. 2020 Mar 18;48(5):2544-2563. doi: 10.1093/nar/gkaa047.
The evolution of gene expression regulation has contributed to species differentiation. The 3' untranslated regions (3'UTRs) of mRNAs include regulatory elements that modulate gene expression; however, our knowledge of their implications in the divergence of bacterial species is currently limited. In this study, we performed genome-wide comparative analyses of mRNAs encoding orthologous proteins from the genus Staphylococcus and found that mRNA conservation was lost mostly downstream of the coding sequence (CDS), indicating the presence of high sequence diversity in the 3'UTRs of orthologous genes. Transcriptomic mapping of different staphylococcal species confirmed that 3'UTRs were also variable in length. We constructed chimeric mRNAs carrying the 3'UTR of orthologous genes and demonstrated that 3'UTR sequence variations affect protein production. This suggested that species-specific functional 3'UTRs might be specifically selected during evolution. 3'UTR variations may occur through different processes, including gene rearrangements, local nucleotide changes, and the transposition of insertion sequences. By extending the conservation analyses to specific 3'UTRs, as well as the entire set of Escherichia coli and Bacillus subtilis mRNAs, we showed that 3'UTR variability is widespread in bacteria. In summary, our work unveils an evolutionary bias within 3'UTRs that results in species-specific non-coding sequences that may contribute to bacterial diversity.
基因表达调控的进化促进了物种分化。mRNA 的 3'非翻译区 (3'UTR) 包含调节基因表达的调控元件;然而,我们目前对它们在细菌物种分化中的意义的了解还很有限。在这项研究中,我们对葡萄球菌属的同源蛋白编码 mRNA 进行了全基因组比较分析,发现 mRNA 的保守性主要在编码序列 (CDS) 下游丢失,表明同源基因的 3'UTR 存在高度的序列多样性。不同葡萄球菌物种的转录组图谱证实 3'UTR 也存在长度的可变性。我们构建了携带同源基因 3'UTR 的嵌合 mRNA,并证明 3'UTR 序列变异会影响蛋白质的产生。这表明在进化过程中,物种特异性的功能 3'UTR 可能被特异性选择。3'UTR 变异可能通过不同的过程发生,包括基因重排、局部核苷酸变化和插入序列的转座。通过将保守性分析扩展到特定的 3'UTR 以及整个大肠杆菌和枯草芽孢杆菌 mRNA 集,我们表明 3'UTR 变异性在细菌中广泛存在。总之,我们的工作揭示了 3'UTR 内的一种进化偏向性,导致了物种特异性的非编码序列,这可能有助于细菌多样性。