Activity of a plasmid-borne leu-500 promoter depends on the transcription and translation of an adjacent gene.
AUTOR(ES)
Chen, D
RESUMO
leu-500 is a chromosomal promoter mutation in Salmonella typhimurium that normally causes the promoter to be inactive in the initiation of RNA synthesis. But in a strain that has mutations in topA, the gene encoding DNA topoisomerase I, the mutant promoter becomes active. We show that the leu-500 promoter can function on a plasmid when it is adjacent to the tetracycline-resistance gene tetA. Activation of the leu-500 promoter requires that the tetA gene is transcribed and translated and that the host cell is topA. We propose that the A----G mutation in the -10 region of the leu-500 promoter is compensated by local negative supercoiling arising from transcription of the tetA gene, which may reach elevated levels in a topA background, provided that diffusional dissipation is reduced due to anchoring of the TetA peptide in the membrane. This is a clear example of the modulation of the activity of a promoter by the activity of another promoter in cis, when they can be coupled through the topology of the template.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=50005Documentos Relacionados
- Activation of the leu-500 promoter by adjacent transcription.
- Topological promoter coupling in Escherichia coli: delta topA-dependent activation of the leu-500 promoter on a plasmid.
- Cloning and sequencing of a plasmid-borne gene (opd) encoding a phosphotriesterase.
- DNA supercoiling and suppression of the leu-500 promoter mutation.
- Bacillus stearothermophilus contains a plasmid-borne gene for alpha-amylase.