Project description:Conventional prokaryotic RNA labeling method usually requires large amounts of starting materials and tends to generate high background signals. Recently, two novel methods based on amplification systems were introduced. Here, we compared three alternative strategies: direct labeling method, ployadenylation-involved oligo-dT priming amplification method and random priming amplification method (hereafter referred to as DL, PAOD and RPA method in this article) for prokaryotic RNA labeling employing the expression profiling investigation in Escherichia coli (E. coli) heat shock model.
Project description:Conventional prokaryotic RNA labeling method usually requires large amounts of starting materials and tends to generate high background signals. Recently, two novel methods based on amplification systems were introduced. Here, we compared three alternative strategies: direct labeling method, ployadenylation-involved oligo-dT priming amplification method and random priming amplification method (hereafter referred to as DL, PAOD and RPA method in this article) for prokaryotic RNA labeling employing the expression profiling investigation in Escherichia coli (E. coli) heat shock model. To identify an optimal RNA labeling method for prokaryotic microarray analysis, experiments were performed with starting RNA obtained from E.coli growing at control (37°C) or heat shock (43°C) condition. We employed 0.5 μg of total RNA for a single round of amplification using PAOD and RPA methods coupling to IVT to generate cDNA targets. In addition, an approach using DL method was also performed. Three types of cDNA mixtures containing Cy5-labeled (or Cy3-labeled) control DNA and Cy3-labeled (or Cy5-labeled) DNA targets were hybridized with E.coli microarrays in a dye-swap strategy. Replicate experiments were conducted from the same batch of total RNA to assess technique reproducibility of each approach.
Project description:Increasing numbers of small proteins with diverse physiological roles are being identified and characterized in both prokaryotic and eukaryotic systems, but the origins and evolution of these proteins remain unclear. Recent genomic sequence analyses in several organisms suggest that new functions encoded by small open reading frames (sORFs) may emerge de novo from noncoding sequences. However, experimental data demonstrating if and how randomly generated sORFs can confer beneficial effects to cells are limited. Here we show that by up-regulating hisB expression, de novo small proteins (≤ 50 amino acids in length) selected from random sequence libraries can rescue Escherichia coli cells that lack the conditionally essential SerB enzyme. The recovered small proteins are hydrophobic and confer their rescue effect by binding to the 5’ end regulatory region of the his operon mRNA, suggesting that protein binding promotes structural rearrangements of the RNA that allow increased hisB expression. This study adds RNA regulatory elements as another interacting partner for de novo proteins isolated from random sequence libraries, and provides further experimental evidence that small proteins with selective benefits can originate from the expression of nonfunctional sequences.
Project description:Total transcript amplification (TTA) from single eukaryotic cells for transcriptome analysis is established, but TTA from a single prokaryotic cell presents additional challenges with much less starting material and lack of poly(A)-tails. We described, here, a novel method for single bacterium TTA, using a Burkholderia thailandensis model exposed to subinhibitory concentration of the antibacterial agent, glyphosate. Utilizing B. thialandensis microarray to assess the TTA method showed little gene bias (< 2 fold-change) and absence (~5-6%) when compared to the larger scale non-amplified RNA samples. B. thailandensis genes important to possibly recuperate and balance the intracellular amino acid pool were induced (or repressed) by the aromatic amino acid biosynthesis inhibitor, glyphosate. We validated our single-cell microarray data at the multi-cells and single-cell levels with lacZ and gfp reporter-gene fusions, respectively. This novel method will rejuvenate and expand the prokaryotic transcriptomic field.
Project description:YajL is the most closely related Escherichia coli homolog of Parkinsonism-associated protein DJ-1, a protein with a yet undefined function in the oxidative stress response. YajL protects cells against oxidative stress-induced protein aggregation and functions as a covalent chaperone for the thiol proteome, including FeS proteins. To clarify the cellular responses to YajL deficiency, transcriptional profiling of the yajL mutant was performed. As compared to the parental strain, the yajL mutant overexpressed genes coding for chaperones, proteases, chemical chaperone transporters, superoxide dismutases, catalases, peroxidases, components of thioredoxin and glutaredoxin systems, iron transporters, ferritins and FeS cluster biogenesis enzymes, DNA-repair proteins, RNA chaperones and small regulatory RNAs. It also overexpressed the RNA polymerase stress sigma factors sigma S (multiple stresses) and sigma 32 (protein stress) and activated the OxyR and SoxRS oxidative stress transcriptional regulators, which together trigger the global stress response. The yajL mutant also overexpressed genes involved in septation and adopted a shorter and rounder shape characteristic of stressed bacteria. Biochemical experiments showed that this upregulation of many stress genes resulted in increased expression of stress proteins and improved biochemical function. Thus, protein defects resulting from the yajL mutation trigger the onset of a robust and global stress response in a prokaryotic model of DJ-1-associated Parkinsonism.
Project description:Purpose: the goals of this study was to find the differential genes of spleen in chickens infected with Escherichia coli Methods: The spleen samples from control group and the spleen samples from infection group were generated by deep sequencing using Illumina system with 9 biological repetitions and 2 technical repetitions, respectively. Results: Using an optimized data analysis workflow, we mapped about 68-91 million sequence reads per sample to the chicken spleens from the infection and control group by Hisat2. Approximately a quarter of the transcripts showed differential expression between the infection and control group, with a 5x SD fold change and p value <0.05.
Project description:B-methylthiolation of the Escherichia coli Ribosomal Protein S12 Regulates Anaerobic Gene Expression. B-methylthiolation is a unique post-translational modification (PTM) that maps to a conserved Asp 88 of the bacterial ribosomal protein S12. This modification is phylogenetically conserved in several bacteria yet has not been identified on other proteins. We use microarrays to delineate the association of prokaryotic ribosomal protein PTM to the regulation of genes.
Project description:Elucidating genome-scale regulatory networks requires a comprehensive collection of gene expression profiles, yet measuring gene expression responses for every transcription factor (TF)-gene pair in living prokaryotic cells remains challenging. Here, we develop pooled promoter responses to TF perturbation sequencing (PPTP-seq) via CRISPR interference to address this challenge. Using PPTP-seq, we systematically measure the activity of 1372 Escherichia coli promoters under single knockdown of 183 TF genes, illustrating more than 200,000 possible TF-gene responses in one experiment. We perform PPTP-seq for E. coli growing under three different media. The PPTP-seq data reveal robust steady-state promoter activities under most single TF knockdown conditions. PPTP-seq also enables identifications of new TF auto-regulatory responses and complex transcriptional control on one-carbon metabolism. We further find context-dependent promoter regulation by multiple TFs whose relative binding strengths determined promoter activities. Additionally, PPTP-seq reveals different promoter responses under different growth media, suggesting condition-specific gene regulation. Overall, PPTP-seq provides a powerful method to examine genome-wide transcriptional regulatory networks and can be potentially expanded to reveal gene expression responses to other genetic elements.