title: Identification of OtpR regulated sRNAs in Brucella melitensis expressed under acidic stress and their roles in pathogenesis and metabolism.
abstract: Small RNAs (sRNAs) are the small regulatory molecules that regulate various biological processes in bacteria. Though the functions of sRNAs are well documented, very little information is available on the sRNAs of Brucella spp. The otpR is the response regulator of a two-component regulatory system, which plays a significant role in Brucella virulence. In this study, we identified the sRNAs expressed in B. melitensis 16M and its otpR mutant under acidic stress from the RNAseq dataset. We identified 94 trans-encoded and 948 cis-encoded sRNAs in B. melitensis 16M. In B. melitensis 16M ΔotpR under acidic stress 99 trans-encoded and 877 cis-encoded sRNAs were identified. Among these, 12 trans-encoded and 43 cis-encoded sRNAs were upregulated in B. melitensis 16M ΔotpR, with an adjusted P-value≤0.05. The mRNA targets of these sRNAs were predicted. Further, the levels of mRNA targets were examined, and the sRNA-mediated regulatory network was predicted. Functional classification and pathway analysis of mRNA targets provided evidence that sRNAs are involved in different metabolic pathways including carbohydrates, amino acids, lipids, nucleotides transport and metabolism, cell membrane biogenesis and intracellular trafficking of Brucella. We also found that eight transcriptional regulators including a quorum sensing regulator, vjbR are down-regulated by sRNAs. These transcriptional regulators might be responsible for the regulation of several other genes in the otpR mutant. The trans-encoded BsnR88 and cis-encoded BsnR980, BsnR998, BsnR881, BsnR1001, BsnR891, BsnR883, BsnR905 are regulating virB operon genes coding for type IV secretion system (T4SS), which is the major virulence factor of Brucella.
authors.affiliation: Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India.
authors.forename: Udayakumar S
authors.initials: US
authors.lastname: Vishnu
authors.affiliation: Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India.
authors.forename: Jagadesan
authors.initials: J
authors.lastname: Sankarasubramanian
authors.affiliation: VIT University, Chennai 600 127, Tamil Nadu, India.
authors.forename: Paramasamy
authors.initials: P
authors.lastname: Gunasekaran
authors.affiliation: Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India. Electronic address: jrajendhran@gmail.com.
authors.forename: Jeyaprakash
authors.initials: J
authors.lastname: Rajendhran
mesh_terms: D000818:Animals; D017347:Brucella melitensis / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006863:Hydrogen-Ion Concentration; D053858:Metabolic Networks and Pathways / Q000235:genetics; D009154:Mutation; D009876:Operon; D053038:Quorum Sensing; D012333:RNA, Messenger / Q000235:genetics; D058727:RNA, Small Untranslated / Q000235:genetics*; D013312:Stress, Physiological; D037521:Virulence Factors / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D058727:RNA, Small Untranslated; D037521:Virulence Factors
keywords: Brucella melitensis; Gene ontology; otpR; sRNA