Identification of the Escherichia coli HU regulon
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ABSTRACT:
ORGANISM(S): Escherichia coli K-12 Escherichia coli
PROVIDER: GSE11183 | GEO | 2009/01/01
SECONDARY ACCESSION(S): PRJNA106883
REPOSITORIES: GEO
Similar Datasets
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.
2009-01-14 | E-GEOD-11183 | biostudies-arrayexpress
Project description:Nucleoid remodeling facilitated by DNA supercoiling results in changes in nucleoid configuration and involves nucleoid-associated proteins (NAPs) and structural maintenance of chromosomes (SMC) proteins among others. Changes in nucleoid configurations regulated by NAPs are synchronized with cellular adaptation and influence the simultaneous expression of several genes. HU, a ubiquitous bacterial histone-like protein, is among the most conserved and abundant NAPs in eubacteria. In Escherichia coli, HU forms dimers by HUα self-association (HUαα) or by HUα-HUβ interactions (HUαβ). HUα is mostly expressed during lag and early exponential growth phase and HUβ is expressed only during the later exponential and stationary phase, pointing to distinct HUαα/DNA and HUαβ/DNA packaging of the nucleoid in regulating expression patterns during growth and stasis. Mutations or the deletion of HU transform the E. coli nucleoid to a different form and alter overall transcription program; thus, HU interactions with DNA directly affect global gene regulation. Recently, analysis of high-resolution contact maps of the E. coli nucleoid revealed an important role of HU to promote long-range DNA-DNA contacts within the nucleoid. Yet, the molecular connections between HU-DNA interactions and changes in nucleoid architecture that regulate gene expression globally remain unknown. Here, we explored the higher-order E. coli nucleoid organization by soft x-ray tomography (SXT) and revealed an effect of HU surface charges in overall nucleoid organization and rearrangements. We also studied global transcription by next-generation RNA sequencing (RNA-Seq) and found a link between nucleoid rearrangement and changes in global transcription. To determine the functional relationships of observed nucleoid rearrangement and HU-DNA interactions, we also characterized the overall organization of HU nucleoprotein complexes in solution by small angle x-ray scattering (SAXS). We found that HUαα-mediated DNA networks are different at different ionic strengths and pHs. By means of macromolecular crystallography, we additionally elucidate HUαα dependent molecular switches that modulate DNA networking. This integrative structural study explains how HUαα regulates dynamic transformations of the nucleoid by DNA bridging to control nucleoid rearrangement and global gene regulation.
2020-04-01 | GSE134667 | GEO
Project description:IHF and HU are two heterodimeric nucleoid associated proteins (NAP) that belong to the same protein family but interact differently with the DNA. IHF is a sequence-specific DNA-binding protein that bends the DNA by over 160o. HU is the most conserved NAP which binds non-specifically to duplex DNA with a particular preference for targeting nicked and bent DNA. Despite their importance, the in-vivo interactions of the two proteins to the DNA remain to be described at a high resolution and on a genome-wide scale. Further, the effects of these proteins on gene expression on a global scale remain contentious. Finally, the contrast between the functions of the homo- and heterodimeric forms of these proteins deserves the attention of further study. Here we present a genome-scale study of HU- and IHF-binding to the E. coli K12 chromosome using ChIP-seq. We also perform microarray analysis of gene expression in single- and double-deletion mutants of each protein to identify their regulons. This data is for microarrays measuring gene expression changes in the various ihf mutants when compared to the wildtype.<br>
2011-11-30 | E-MEXP-3461 | biostudies-arrayexpress
Project description:High-resolution transcriptional profiling of E. coli across nine timepoints of growth in rich media (LB). Samples collected from lag phase to stationary phase of growth. High-resolution tiling array to detect conditional operon isoforms. Custom Agilent array designed to detect condition-specific transcriptional isoforms. Array designed for E coli K12 MG1655 genome. Tiled using 23bp sliding window. Includes >10,000 probes surrounding predicted operon break sites at 6 bp resolution.
2014-07-22 | GSE55879 | GEO
Project description:HU is a conserved prokaryotic nucleoid-associated protein known for its role in DNA binding and maintaining negative supercoils in DNA. HU also binds to a few RNAs but the natural targets are unknown. To understand the biology of HU interactions with RNA in Escherichia coli, potential HU-RNA in vivo complexes were immunoprecipitated and bound RNAs were examined by hybridization to whole-genome tiling arrays. We observed HU associations with rRNA, multiple tRNAs, a few sRNAs and a small, distinct set of mRNAs. More importantly, we also identified associations between HU and ten intragenic non-coding (nonc) RNAs, two of which are homologous to the annotated Bacterial Interspersed Mosaic Elements (BIME) and boxC elements; the other eight RNAs have not been annotated. We confirmed binding of HU to BIME RNA in vitro. Since HU and some unidentified RNAs have been implicated in the nucleoid structure, we explored an idea that HU, along with some or all of the nonc RNA species discovered here bind to BIME and/or boxC repeats to condense chromosomal DNA in a specific fashion. We propose that nonc RNAs may interact with both HU and DNA repeats to form ternary complexes, which are the anchoring points separating different chromosomal domains.
2012-12-07 | GSE28565 | GEO
Project description:Determination of the genome-wide distribution of ORC by chromatin immunoprecipitation in the Drosophila Kc167 cell line at the beginning of S phase. Kc167 cells were arrested at the G1/S transition with hydroxyurea (HU). Goal was to test whether the ORC binding distribution remained the same between G1 and S. ChIP-Chip of ORC in HU compared to input genomic DNA. Biological Replicates: 1
2014-12-05 | E-GEOD-63914 | biostudies-arrayexpress
Project description:Lysine acetylation is a prevalent post-translational modification in both eukaryotes and prokaryotes. Whereas this modification is known to play pivotal roles in eukaryotes, the function and extent of this modification in prokaryotic cells remain largely unexplored. Here we report the acetylome of a pair of antibiotic-sensitive and -resistant nosocomial pathogen Acinetobacter baumannii SK17-S and SK17-R. A total of 145 lysine acetylation sites on 125 proteins was identified, and there are 23 acetylated proteins found in both strains, including histone-like protein HU which was found to be acetylated at Lys13. HU is a dimeric DNA-binding protein critical for maintaining chromosomal architecture and other DNA-dependent functions. To analyze the effects of site-specific acetylation, homogenously Lys13-acetylated HU protein, HU(K13ac) was prepared by genetic code expansion. Whilst not exerting an obvious effect on the oligomeric state, Lys13 acetylation alters both the thermal stability and DNA binding kinetics of HU. Accordingly, this modification likely destabilizes the chromosome structure and regulates bacterial gene transcription. By preparing and characterizing site-specifically acetylated bacterial protein for the first time, this work indicates that acetyllysine plays an important role in bacterial epigenetics and presents a promising target against bacterial infections.
2018-10-24 | PXD007289 | Pride
Project description:High-resolution transcriptional profiling of E. coli across nine timepoints of growth in rich media (LB). Samples collected from lag phase to stationary phase of growth. High-resolution tiling array to detect conditional operon isoforms. Custom Agilent array designed to detect condition-specific transcriptional isoforms. Array designed for E coli K12 MG1655 genome. Tiled using 23bp sliding window. Includes >10,000 probes surrounding predicted operon break sites at 6 bp resolution. Nine growth time points in the experiment. Two-color arrays. Each time point compared to mid-exponential phase of growth.
2014-07-22 | E-GEOD-55879 | biostudies-arrayexpress
Project description:Determination of the genome-wide distribution of ORC by chromatin immunoprecipitation in the Drosophila Kc167 cell line at the beginning of S phase. Kc167 cells were arrested at the G1/S transition with hydroxyurea (HU). Goal was to test whether the ORC binding distribution remained the same between G1 and S.
2014-12-05 | GSE63914 | GEO
Project description:Determination of the genome-wide distribution of the Mcm2-7 helicase by chromatin immunoprecipitation in the Drosophila Kc167 cell line at the beginning of S phase. Kc167 cells were arrested at the G1/S transition with hydroxyurea (HU). Goal was to evaluate changes in the genome-wide Mcm2-7 distribution throughout the cell cycle, and how this relates to the excess Mcm2-7 loaded onto chromatin in G1. ChIP-Chip of Mcm2-7 in HU compared to input genomic DNA. Biological Replicates: 2
2014-11-27 | E-GEOD-63680 | biostudies-arrayexpress