Genomic analysis of the combined effects of H-NS and co-regulators on E. coli gene expression
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ABSTRACT: This entry refers to transcriptome analysis of E. coli with single deletions of hns, stpA, hha and ydgT and double deletions of hns with each of the other three regulators mentioned. 8 samples with 2 replicates each
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
Project description:An oligonucleotide tiling array technology is utilized to measure the entire Escherichia coli transcriptome and its transcriptional changes after induction of the adaptive response by the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Keywords: Gene expression during the adaptive response in Escherichia coli Escherichia coli K-12 MG1655 single colony in five parallells was grown to mid-log phase and exposed to the ada-response inducer MNNG. Total RNA was extracted from induced and uninduced cells and cDNA was prepared, fragmented and labelled prior to hybridizing to arrays. The Escherichia coli genome was split in two; sequences encoding proteins, tRNAs or rRNAs with a known function on either strand, and sequences without such annotation. A selective tiling approach was used to ensure sufficient coverage of unnanotated genomic regions due to the limited number of array probes.
Project description:The transcriptional changes in Escherichia coli upon induction of the SOS response are investigated by utilizing custom designed oligonucleotide microarrays. Keywords: Gene expression during the SOS response in Escherichia coli Escherichia coli K-12 MG1655 single colony in five parallells was grown to mid-log phase and exposed to UV to induce the SOS response. Total RNA was extracted from induced and uninduced cells and cDNA was prepared, fragmented and labelled prior to hybridizing to arrays. The arrays was designed to maximize the genomic coverage whilst simultaneous including only probes estimated to give an approximately uniform binding affinity. Regions coding for non-hypothetical proteins or RNAs where covered less densely than the intergenic parts.
Project description:Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 ?fnr mutant, compared to the wild-type strain. The mutations engineered into this strain produce a strain lacking the FNR protein. WT strains were grown under aerobic and anaerobic growth conditions. A six chip study using total RNA recovered from two separate cultures of Escherichia coli MG1655 K-12 WT (aerobic and anaerobic) and two separate cultures of the ?fnr mutant strain (anaerobic). Each chip measures the expression level of 4,661 genes from Escherichia coli MG1655 K-12 with eight 60-mer probes per gene, with each probe represented twice on the array.
Project description:Background Bovine Spastic Paresis (BSP) is a neuromuscular disorder which affects both male and female cattle. BSP is characterized by spastic contraction and overextension of the gastrocnemious muscle of one or both limbs and is associated with a scarce increase in body weight. This disease seems to be caused by an autosomal and recessive gene, with incomplete penetration, although no genes clearly involved with its onset have been so far identified. We employed cDNA microarrays to identify metabolic pathways affected by BSP in Romagnola cattle breed. Investigation of those pathways at the genome level can help to understand this disease. Results Microarray analysis of control and affected individuals resulted in 268 differentially expressed genes. These genes were subjected to KEGG pathway functional clustering analysis, revealing that they are predominantly involved in Cell Communication, Signalling Molecules and Interaction and Signal Transduction, Diseases and Nervous System classes. Significantly enriched KEGG pathwayM-bM-^@M-^Ys classes for the differentially expressed genes were calculated; interestingly, all those significantly under-expressed in the affected samples are included in Neurodegenerative Diseases. To identify genome locations possibly harbouring gene(s) involved in the disease, the chromosome distribution of the differentially expressed genes was also investigated. Conclusions The cDNA microarray we used in this study contains a brain library and, even if carrying an incomplete transcriptome representation, it has proven to be a valuable tool allowing us to add useful and new information to a poorly studied disease. By using this tool, we examined nearly 15000 transcripts and analysed gene pathways affected by the disease. Particularly, our data suggest also a defective glycinergic synaptic transmission in the development of the disease and an alteration of calcium signalling proteins. We provide data to acquire knowledge of a genetic disease for which literature still presents poor results and that could be further and specifically analysed in the next future. Moreover this study, performed in livestock, may also harbour molecular information useful for understanding human diseases. Samples of spinal cord from 4 affected and 4 control individuals of the Romagnola breed were collected immediately after slaughtering and later stored in RNA (Sigma-Aldrich). Dye-swaps were performed using pooled cDNA probes from the 4 control animals and the 4 affected animals.
Project description:Differential expression of genes in E. coli MG1655 strains with deletions of fis and hns was assessed under early-exponential, mid-exponential, transition-to-stationary and stationary phases of growth in LB medium.
Project description:Here, we report the comparison of transcriptomes of Anabaena sp. PCC7120 and a FurC-overexpressing derivative strain grown under standard conditions (BG11) and after 48 hours of nitrogen step-down (BG110). Anabaena sp PCC7120 is a cyanobacterium that differentiates specialized nitrogen-fixing cells called heterocysts. Our data suggests that FurC directly controls the regulation of heterocyst differentiation and nitrogen fixation in this cyanobacterium. In addition, we found that FurC is also clearly involved in the regulation of several genes belonging to different functional categories, such as iron metabolism, photosynthesis and regulatory functions.