The lac operon shows anomalous expression in Proteus mirabilis: the maximal induced level is 10% or less of that in E. coli, while repression reduces this by a factor of only 2-5. We have sought to determine whether this effect relates in any way to CRP-mediated activation of expression, by comparin
Anomalous expression of the E. coli lac operon in Proteus mirabilis
β Scribed by Baumberg, Simon ;Roberts, Margo
- Publisher
- Springer
- Year
- 1986
- Tongue
- English
- Weight
- 44 KB
- Volume
- 204
- Category
- Article
- ISSN
- 0026-8925
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β¦ Synopsis
We were kindly provided by Z. al-Doori (Dept. of Molecular Biology, University of Edinburgh) with a hybrid plasmid produced by in vitro techniques, pZD23 (A1- Doori et al. 1982). This plasmid is derived from pZD100, which consists of a 2drpoBC18 (=2drpoB3) prophage inserted into RP42att, by a deletion which has removed almost all 2 sequences leaving the host cell non-temperature-sensitive.
π SIMILAR VOLUMES
The lac operon introduced into Proteus mirabilis shows two anomalies of expression: the maximal induced level is reduced by about an order of magnitude, and the basal level becomes about 100 times higher than in E. coli, as a result of which the induction ratio appears very small, around 2-5 in cont
The expression and stability of Escherichia coli F-primes in Proteus mirabilis is examined. It is possible to consecutively introduce, and stably maintain, the DNA of several E. coli F-primes in P. mirabilis in the absence of selective pressure for all or some of the plasmids. Additionally, we can r
Three temperature-sensitive mutant strains for RNA polymerase beta or beta' subunits (carrying mutations tsx, A2R7 and R120) were used in order to investigate the dependence of the induced lac expression on stimulation by cyclic AMP after the shift to non-permissive temperature. High temperature low
Various Escherichia coli K12 Hfr donors transfer at low frequency portions of the E. coli genome to Proteus mirabilis. By remating such Proteus hybrids with the same or a different E. coli Hfr strain, other genetic characters could be added to yield diploid Proteus hybrids which contained more than