UCL logo

UCL Discovery

UCL home » Library Services » Electronic resources » UCL Discovery

Reduced expression of Tn 10-mediated tetracycline resistance in Escherichia coli containing more than one copy of the transposon.

Chopra, I; Shales, SW; Ward, JM; Wallace, LJ; (1981) Reduced expression of Tn 10-mediated tetracycline resistance in Escherichia coli containing more than one copy of the transposon. J Gen Microbiol , 126 (1) pp. 45-54. 10.1099/00221287-126-1-45.

Full text not available from this repository.

Abstract

In Escherichia coli a single copy of Tn10 confers high-level resistance to tetracycline. Resistance itself results from expression of three distinct mechanisms which normally act together (Shales et al., 1980). In cells containing two copies of Tn10, the level of resistance to tetracycline was reduced. This was not due to overproduction of the repressor which controls the resistance genes, because strains diploid for an operator-constitutive allele of Tn10 also exhibited reduced expression of resistance. The negative gene dosage effect resulted from decreased expression of two mechanisms (1 and 2) consequent on enhanced expression of the third mechanism. The net result of increasing the copy number was a decrease in resistance because mechanism 3 was less efficient than mechanisms 1 and 2 in protecting the cell against tetracycline. The DNA sequence responsible for the reduced expression of resistance was contained in the internal BglII fragment of Tn10. This sequence, which is probably unique to Tn10, may encode the protein which mediates mechanism 3. Elevated levels of this protein probably cause decreased expression of mechanisms 1 and 2.

Type: Article
Title: Reduced expression of Tn 10-mediated tetracycline resistance in Escherichia coli containing more than one copy of the transposon.
Location: England
DOI: 10.1099/00221287-126-1-45
Keywords: DNA Transposable Elements, Diploidy, Escherichia coli, Gene Expression Regulation, Genes, Regulator, Minocycline, R Factors, Tetracycline, Transcription, Genetic
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Biochemical Engineering
URI: http://discovery.ucl.ac.uk/id/eprint/1419836
Downloads since deposit
0Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item