UV treated Escherichia coli reveals a high number of differentially expressed regions and many novel transcripts

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.