Project description:In this study transcriptional start sites (TSS) of E. coli were determined for several growth conditions To detect the complement of transcripts expressed from E. coli, we collected two independent biological replicates (B1 and B2 samples) from MG1655 wild type strain grown to exponential (OD 600 ~0.4) or stationary phase (OD 600 ~2.0) in LB medium (samples LB 0.4 and LB 2.0, respectively) as well as grown to exponential phase (OD 600 ~0.4) in M63 minimal glucose medium (sample M63 0.4). For all six 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 5M-bM-^@M-^Y terminator exonuclease (+TEX samples), which degrades RNAs containing a 5M-bM-^@M-^Y-mono-phosphate (5M-bM-^@M-^Y-P) and, thus, enriching enriches for primary transcripts containing 5M-bM-^@M-^Y-tri-phosphates (5M-bM-^@M-^Y-PPP). The other half of each sample was left untreated (-TEX samples) and thus contains both primary transcripts (5M-bM-^@M-^Y-PPP) and processed RNAs (5M-bM-^@M-^Y-P).
Project description:The physiological role of the various nucleoid-associated proteins in bacteria and HU in particular has been addressed in a number of studies but remains so far not fully understood. In this work, a genome-wide microarray hybridization approach, combined with in vivo genetic experimentation, has been performed in order to compare and evaluate the effect of HUalpha, HUbeta and HUalphabeta on the transcription of the Escherichia coli K12 genes as a function of growth phase. The histone-like protein HU is present in the E. coli cell under three dimeric forms (HUalphabeta, HUalpha2 and HUbeta2) in a ratio that varies with growth phase. The experimental protocol is designed to handle strain genotype and growth phase as independent variables. Experiment Overall Design: We used microarrays to investigate global bacterial gene expression in five genotypes of E. coli C600: WT (JO2057), hupA (JO2081), hupB (JO2083), hupAB (JO3020) and rpoS (MW30) at three growth growth phases: exponential, transition and stationary and in three growth media: LB, M9 minimal Glucose and M9 minimal Glycerol. The most relevant experiments were carried out in duplicate: the wild type (JO2057) and the hupAB (JO3020) strains were tested in the exponential and stationary phase, in LB. Wild type and hupAB strains were also tested in single experiments at the transition phase in LB. The single hupA (JO2081) and single hupB (JO2083) mutants were tested at the three growth phases in LB. Wild type and hupAB strains were compared in single experiments both in M9 Minimal Glucose and M9 Minimal Glycerol at the exponential and stationary phase. The last chips were used to test respectively the rpoS mutant at the at the exponential and stationary phase in LB.
Project description:We have deep sequenced the small transcriptome of Escherichia coli growing in LB and in MOPS, in exponential and stationary phase, and analyzed the resulting reads by a novel pipeline STARPA (Stable RNA Processing Product Analyzer). Our analysis reveals over 14,000 small transcripts enriched during both growth stages. RNA samples were collected from total RNA pools or from crude ribosome pools and then size selected by electrophoresis to limit the products to 20-300nt.
Project description:Responses of Escherichia coli as they recover from one stationary phase in 10 mM Na-P + 0.2 % glucose at OD 0.4 Keywords: time course