Propagation of ectopic DNA in E. coli host cells is central to molecular biology. DNA constructs are often engineered for expression of recombinant protein in E. coli, but the extent of incidental transcription arising from natural regulatory sequences in cloned DNA remains under explored. We have used programmable microarrays and RT-PCR to measure, comprehensively, the transcription of H. influenzae, P. aeruginosa and human DNA propagating in E. coli as Bacterial Artificial Chromosomes. We find evidence that at least half of all H. influenzae genes are transcribed in E. coli. Highly transcribed genes are principally involved in energy metabolism and their proximal promoter regions are significantly enriched with E. coli sigma70 binding sites. Compared to H. influenzae, a smaller proportion of P.aeruginosa genes are transcribed in E. coli, and in E. coli there is punctuated transcription of human DNA. Ongoing characterization of cross-expression will help inform the design of biosynthetic gene clusters and synthetic microbial genomes.
Full citationWarren RL, Freeman JD, Levesque RC, Smailus DE, Flibotte S, Holt RA. Transcription of foreign DNA in Escherichia coli. Genome Research. Published online before print August 13, 2008
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