Lloréns Rico, Verónica, 1989-Cano, JaimeKamminga, TjerkoGil, RosarioLatorre, AmparoChen, Wei-HuaBork, PeerGlass, John I.Serrano Pubull, Luis, 1982-Lluch-Senar, Maria 1982-2017-04-262017-04-262016Lloréns-Rico V, Cano J, Kamminga T, Gil R, Latorre A, Chen W-H, Bork P, Glass JI, Serrano L, Lluch-Senar M. Bacterial antisense RNAs are mainly the product of transcriptional noise. Science Advances. 2016;2(3):e150363. DOI: 10.1126/sciadv.15013632375-2548http://hdl.handle.net/10230/30911cis-Encoded antisense RNAs (asRNAs) are widespread along bacterial transcriptomes. However, the role of most of these RNAs remains unknown, and there is an ongoing discussion as to what extent these transcripts are the result of transcriptional noise. We show, by comparative transcriptomics of 20 bacterial species and one chloroplast, that the number of asRNAs is exponentially dependent on the genomic AT content and that expression of asRNA at low levels exerts little impact in terms of energy consumption. A transcription model simulating mRNA and asRNA production indicates that the asRNA regulatory effect is only observed above certain expression thresholds, substantially higher than physiological transcript levels. These predictions were verified experimentally by overexpressing nine different asRNAs in Mycoplasma pneumoniae. Our results suggest that most of the antisense transcripts found in bacteria are the consequence of transcriptional noise, arising at spurious promoters throughout the genome.application/pdfengCopyright © 2016, The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited. DOI: 10.1126/sciadv.1501363info:eu-repo/semantics/articlehttp://dx.doi.org/10.1126/sciadv.1501363RNABacterial antisense RNAsinfo:eu-repo/semantics/openAccess