ABSTRACT: We combined high-resolution tiling microarrays and 5'-end RNA sequencing to obtain a genome-wide map of transcription start sites (TSSs) for Shewanella oneidensis MR-1. To test the reliability of these TSSs, we compared our result to those from differential RNA sequencing (dRNA-seq), which discriminates primary and processed ends of transcripts. We found that our identified TSSs tend to have significantly more mapped reads in the TEX(+) sample than the TEX(-) sample. Overall, the dRNA-seq results support the validity of our predictions for TSS. S. oneidensis MR-1 was grown to mid-log phase in Luria-Bertani broth (LB) or defined lactate minimal medium, and total RNA was isolated and used for differential RNA-sequencing (dRNA-seq) by next-generation sequencing, which is used to verify genome-wide transcription start sites. For dRNA-seq, total RNA was partially treated with Terminator Exonuclease (TEX) to digest processed RNA and thereby enrich for primary transcript ends.
Project description:5' RNA-Seq of mRNA from S. oneidensis MR-1 grown aerobically in defined lactate medium One lane of sequence for a 5' RNASeq library from RNA treated with exonuclease to remove degraded transcripts, with single-end 40-nt reads
Project description:Comparison of gene expression and mutant fitness in Shewanella oneidensis MR-1 Expression data for 15 growth conditions in mid-exponential phase and expression data across growth phases for 3 of those conditions
Project description:The sumitted data compares gene expression profile of Shewnaella oneidensis MR-1 on two different sets of media conditions (nutritionally rich LB medium and Lactate minimal medium) To explore the effect of various growth phases in Shewanella oneidensis MR-1, the genome-wide transcriptome profiles growth in two sets media was compared to each other. Strain was grown in chemostat at 20% O2 in batch culture. Samples were collected in duplicate from both experiments.
Project description:Stenotrophomonas maltophilia is an important opportunistic pathogen affecting primarily hospitalized and immuno-compromised hosts. We constructed an hfq deletion mutant (Delta-hfq) of S. maltophilia, and compared the behaviour of wild-type and Delta-hfq S. maltophilia cells in a variety of assays. Differential RNA sequencing analysis (dRNA-seq) of RNA isolated from S. maltophilia wild-type and Delta-hfq strains showed that Hfq regulates expression of genes encoding flagellar and fimbrial components, transmembrane proteins, as well as enzymes involved in different metabolic pathways. Moreover, we analysed expression of several sRNAs identified by dRNA-seq in wild-type. The accumulation of two sRNAs was strongly reduced in the absence of Hfq. TEX (terminator exonuclease) treated and untreated libraries of the wild type and the Delta-hfq mutant were sequenced and compared
Project description:We investigated the anode-specific responses of Shewanella oneidensis MR-1, an exoelectroactive ammaproteobacterium, using for the first time iTRAQ and 2D-LC MS/MS driven membrane proteomics to compare protein abundances in S. oneidensis when generating power in MFCs, and growing in a continuous culture.
Project description:Transcription start sites (TSSs) lying inside annotated genes, on the same or opposite strand, have been observed in diverse bacteria, but the function of these unexpected transcripts is unclear. Here, we use the metal-reducing bacterium Shewanella oneidensis MR-1 and its relatives to study the evolutionary conservation of unexpected TSSs. Using high-resolution tiling microarrays and 5'-end RNA sequencing, we identified 2,531 TSSs in S. oneidensis MR-1, of which 18% were located inside coding sequences (CDSs). Comparative transcriptome analysis with seven additional Shewanella species revealed that the majority (76%) of the TSSs within the upstream regions of annotated genes (gTSSs) were conserved. Thirty percent of the TSSs that were inside genes and on the sense strand (iTSSs) were also conserved. Sequence analysis around these iTSSs showed conserved promoter motifs, suggesting that many iTSS are under purifying selection. Furthermore, conserved iTSSs are enriched for regulatory motifs, suggesting that they are regulated, and they tend to eliminate polar effects, which confirms that they are functional. In contrast, the transcription of antisense TSSs located inside CDSs (aTSSs) was significantly less likely to be conserved (22%). However, aTSSs whose transcription was conserved often have conserved promoter motifs and drive the expression of nearby genes. Overall, our findings demonstrate that some internal TSSs are conserved and drive protein expression despite their unusual locations, but the majority are not conserved and may reflect noisy initiation of transcription rather than a biological function. Importance: The first step of gene expression is the initiation of transcription from promoters, which have been traditionally thought to be located upstream of genes. Recently, studies showed that in diverse bacteria, promoters are often located inside genes. It has not been clear if these unexpected promoters are important to the organism or if they result from transcriptional noise. Here, we identify and examine promoters in eight related bacterial species. Promoters that lie within genes on the sense strand are often conserved as locations and in their sequences. Furthermore, these promoters often affect the bacterium's growth. Thus, many of these unexpected promoters are likely functional. Fewer promoters that lie within genes on the antisense strand are conserved, but the conserved ones seem to drive the expression of nearby genes.
Project description:In this study transcriptional start sites (TSS) for H. pylori 26695 were determined To detect the complement of transcripts expressed from H. pylori, we collected three independent biological replicates (B1 – B3) from 26695 wild type strain grown to mid-exponential (OD 600 ~0.6) phase under microaerophilic conditions at 37°C in BHI medium. For all three samples, total RNA was extracted and subjected to differential RNA-seq (dRNA-seq) library preparation for primary transcriptome analysis as described previously (Sharma et al., 2010). Specifically, prior to cDNA library construction half of each RNA sample was treated with 5’ terminator exonuclease (+TEX samples), which degrades RNAs containing a 5’-monophosphate (5’-P) and, thus, enriches for primary transcripts containing 5’-triphosphates (5’-PPP). The other half of each sample was left untreated (-TEX samples) and thus contains both primary transcripts (5’-PPP) and processed RNAs (5’-P).
Project description:5' RNASeq of mRNA from S. oneidensis MR-1 grown aerobically in Luria-Bertani broth (LB) and defined lactate minimal medium 5'-end mRNA profiles of mid-log phase bacterial cells growing in LB or lactate medium were generated by next-generation sequencing.
Project description:We have used differential RNA-seq (dRNA-seq) to characterise the transcriptomic architecture of S. Typhimurium SL1344, and its dependence on the bacterial alarmone, guanosine tetraphosphate (ppGpp) during late stationary phase, (LSP). Under LSP conditions we were able to identify the transcriptional start sites (TSSs) for 53% of the S. Typhimurium open reading frames (ORFs) and discovered 282 candidate non-coding RNAs (ncRNAs). The mapping of LSP TSSs enabled a detailed comparison with a previous dRNA-seq study of the early stationary phase (ESP) transcriptional architecture of S. Typhimurium SL1344 and its dependence on ppGpp. For the purposes of this study, LSP was defined as an aerobic LB culture grown to a later optical density reading (OD600?=?3.6) compared to ESP (OD600?=?2.3). The precise nucleotide positions of the majority of S. Typhimurium TSSs at LSP agreed closely with those identified at ESP. However, the identification of TSSs at different positions, or where additional or fewer TSSs were found at LSP compared to ESP enabled the genome-wide categorisation of growth phase dependent changes in promoter structure, the first time such an analysis has been done on this scale. Comparison of the ppGpp-dependency LSP and ESP TSSs for mRNAs and ncRNAs revealed a similar breadth of ppGpp-activation and repression. However, we note several ncRNAs previously shown to be involved in virulence were highly ppGpp-dependent at LSP. Finally, although SPI1 was expressed at ESP, we found SPI1 was not as highly expressed at LSP, instead we observed elevated expression of SPI2 encoded genes. We therefore also report an analysis of SPI2 transcriptional architecture at LSP resulting in localisation of SsrB binding sites and identification of a previously unreported SPI2 TSS. We also show that ppGpp is required for nearly all of SPI2 expression at LSP as well as for expression of SPI1 at ESP.