Journal of Microbiology

Characterization of promotor sequences for strong expression of groEx IN Escherichia coli.: Lee, Jung E. , Lim, Ssang T. , Aha, Tae I.; J. Microbiol. 1996;34(1):15-22.

Abstract: The cloned X-bacterial gene (groEx) which is analogous to groE of E. Coli strongly expressed in E. coli when grown at the temperature 27℃ or higher without having to add any inducers. By S1-nuclease mapping, primer extension analysis and site directed mutagenesis, we found 4 promoters in the gene. Among them two promoters located at 5'-extended region of the gene are homologous to the promoters found in groE family of heat-shock genes ; they are , σ^32 factor-dependent P1 promotor and σ^70 factor-dependet P2 promoter. The other two promoters found within the coding region of groESx were P3, 5'-TTGGCG-(18 bases)-AATACT-3' and P4, 5'-TTGGCA-(19 bases)-TAAGT which overlapped within 49 bases. These unique intragenic σ^70-dependent promoters are the first to be cloned and characterized in groE analogous heat-shock genes so far. These P3 and P4 promoters appeared to be responsible for the strong expression of GroElx in X-bacteria in vivo.

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