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Small RNAs that target G‐rich sequences are generated by diverse biogenesis pathways in Epsilonproteobacteria
Author(s) -
Svensson Sarah L.,
Sharma Cynthia M.
Publication year - 2022
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14850
Subject(s) - biology , genetics , campylobacter jejuni , biogenesis , rnase p , gene , untranslated region , virulence , flagellin , transfer rna , rna , bacteria
Bacterial small RNAs (sRNAs) are widespread post‐transcriptional regulators that control bacterial stress responses and virulence. Nevertheless, little is known about how they arise and evolve. Homologs can be difficult to identify beyond the strain level using sequence‐based approaches, and similar functionalities can arise by convergent evolution. Here, we found that the virulence‐associated CJnc190 sRNA of the foodborne pathogen Campylobacter jejuni resembles the RepG sRNA from the gastric pathogen Helicobacter pylori . However, while both sRNAs bind G‐rich sites in their target mRNAs using a C/U‐rich loop, they largely differ in their biogenesis. RepG is transcribed from a stand‐alone gene and does not require processing, whereas CJnc190 is transcribed from two promoters as precursors that are processed by RNase III and also has a cis ‐encoded antagonist, CJnc180. By comparing CJnc190 homologs in diverse Campylobacter species, we show that RNase III‐dependent processing of CJnc190 appears to be a conserved feature even outside of C. jejuni . We also demonstrate the CJnc180 antisense partner is expressed in C. coli , yet here might be derived from the 3’UTR (untranslated region) of an upstream flagella‐related gene. Our analysis of G‐tract targeting sRNAs in Epsilonproteobacteria demonstrates that similar sRNAs can have markedly different biogenesis pathways.