title: Small Open Reading Frames, Non-Coding RNAs and Repetitive Elements in Bradyrhizobium japonicum USDA 110.
abstract: Small open reading frames (sORFs) and genes for non-coding RNAs are poorly investigated components of most genomes. Our analysis of 1391 ORFs recently annotated in the soybean symbiont Bradyrhizobium japonicum USDA 110 revealed that 78% of them contain less than 80 codons. Twenty-one of these sORFs are conserved in or outside Alphaproteobacteria and most of them are similar to genes found in transposable elements, in line with their broad distribution. Stabilizing selection was demonstrated for sORFs with proteomic evidence and bll1319_ISGA which is conserved at the nucleotide level in 16 alphaproteobacterial species, 79 species from other taxa and 49 other Proteobacteria. Further we used Northern blot hybridization to validate ten small RNAs (BjsR1 to BjsR10) belonging to new RNA families. We found that BjsR1 and BjsR3 have homologs outside the genus Bradyrhizobium, and BjsR5, BjsR6, BjsR7, and BjsR10 have up to four imperfect copies in Bradyrhizobium genomes. BjsR8, BjsR9, and BjsR10 are present exclusively in nodules, while the other sRNAs are also expressed in liquid cultures. We also found that the level of BjsR4 decreases after exposure to tellurite and iron, and this down-regulation contributes to survival under high iron conditions. Analysis of additional small RNAs overlapping with 3'-UTRs revealed two new repetitive elements named Br-REP1 and Br-REP2. These REP elements may play roles in the genomic plasticity and gene regulation and could be useful for strain identification by PCR-fingerprinting. Furthermore, we studied two potential toxin genes in the symbiotic island and confirmed toxicity of the yhaV homolog bll1687 but not of the newly annotated higB homolog blr0229_ISGA in E. coli. Finally, we revealed transcription interference resulting in an antisense RNA complementary to blr1853, a gene induced in symbiosis. The presented results expand our knowledge on sORFs, non-coding RNAs and repetitive elements in B. japonicum and related bacteria.
authors: Institute of Microbiology and Molecular Biology, Justus-Liebig-University, Giessen, Germany.
authors: Julia
authors: J
authors: Hahn
authors: A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Bolshoi Karetny Ln. 19, Moscow, 127051, Russia.
authors: Olga V
authors: OV
authors: Tsoy
authors: Institute of Microbiology and Molecular Biology, Justus-Liebig-University, Giessen, Germany.
authors: Sebastian
authors: S
authors: Thalmann
authors: A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Bolshoi Karetny Ln. 19, Moscow, 127051, Russia.|ETH, Institute of Molecular Systems Biology, Zürich, Switzerland.
authors: Jelena
authors: J
authors: Čuklina
authors: A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Bolshoi Karetny Ln. 19, Moscow, 127051, Russia.|Skolkovo Institute of Science and Technology, Nobel Str. 3, Moscow, 143026, Russia.|Faculty of Bioengineering and Bioinformatics, M. V. Lomonosov Moscow State University, Vorobyevy Gory 1-73, Moscow, 119234, Russia.|Faculty of Computer Science, Higher School of Economics, Kochnovsky Dr. 3, Moscow, 125319, Russia.
authors: Mikhail S
authors: MS
authors: Gelfand
authors: Institute of Microbiology and Molecular Biology, Justus-Liebig-University, Giessen, Germany.
authors: Elena
authors: http://orcid.org/0000-0001-7270-3168
authors: E
authors: Evguenieva-Hackenberg
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D001483:Base Sequence; D020369:Bradyrhizobium / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D017124:Conserved Sequence; D015536:Down-Regulation / Q000187:drug effects; D007501:Iron / Q000494:pharmacology; D016366:Open Reading Frames / Q000235:genetics*; D012329:RNA, Bacterial / Q000235:genetics*; D022661:RNA, Untranslated / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D014118:Toxins, Biological / Q000235:genetics
chemical_list: D020413:3' Untranslated Regions; D012329:RNA, Bacterial; D022661:RNA, Untranslated; D014118:Toxins, Biological; D007501:Iron