TY - JOUR TI - RNase III-mediated processing of a trans-acting bacterial sRNA and its cis-encoded antagonist AU - Svensson, Sarah Lauren AU - Sharma, Cynthia Mira A2 - Contreras, Lydia A2 - Storz, Gisela VL - 10 PY - 2021 DA - 2021/11/29 SP - e69064 C1 - eLife 2021;10:e69064 DO - 10.7554/eLife.69064 UR - https://doi.org/10.7554/eLife.69064 AB - Bacterial small RNAs (sRNAs) are important post-transcriptional regulators in stress responses and virulence. They can be derived from an expanding list of genomic contexts, such as processing from parental transcripts by RNase E. The role of RNase III in sRNA biogenesis is less well understood despite its well-known roles in rRNA processing, RNA decay, and cleavage of sRNA-mRNA duplexes. Here, we show that RNase III processes a pair of cis-encoded sRNAs (CJnc190 and CJnc180) of the food-borne pathogen Campylobacter jejuni. While CJnc180 processing by RNase III requires CJnc190, RNase III processes CJnc190 independent of CJnc180 via cleavage of an intramolecular duplex. We also show that CJnc190 directly represses translation of the colonization factor PtmG by targeting a G-rich ribosome-binding site, and uncover that CJnc180 is a cis-acting antagonist of CJnc190, indirectly affecting ptmG regulation. Our study highlights a role for RNase III in sRNA biogenesis and adds cis-encoded RNAs to the expanding diversity of transcripts that can antagonize bacterial sRNAs. KW - Campylobacter jejuni KW - small regulatory RNA KW - sRNA KW - RNase III KW - post-transcriptional regulation KW - pathogenesis JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -