In Escherichia coli the iron uptake systems are regulated by the fur gene product. The synthesis of the outer membrane proteins fiu, fepA, fecA, fhuA, fhuE and cir is derepressed at low iron concentrations in the medium or constitutive in a fur mutant. The fur gene region cloned into pACYC184 was an
Cloning of phoM, a gene involved in regulation of the synthesis of phosphate limitation inducible proteins in Escherichia coli K12
โ Scribed by Tommassen, Jan ;Hiemstra, Pieter ;Overduin, Piet ;Lugtenberg, Ben
- Publisher
- Springer
- Year
- 1984
- Tongue
- English
- Weight
- 619 KB
- Volume
- 195
- Category
- Article
- ISSN
- 0026-8925
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โฆ Synopsis
Like the synthesis of alkaline phosphatase, the synthesis of outer membrane PhoE protein is shown to be dependent on the phoM gene product in phoR mutants of E. coli K12. This phoM gene has been cloned into the multi-copy vector pACYC184 using selection for alkaline phosphatase constitutive synthesis in a phoR background. The gene was localized on the hybrid plasmids by analysis of deletion plasmids constructed in vitro and of mutant plasmids generated by gamma delta insertions. Interestingly, two of the selected hybrid plasmids contained the entire phoA-phoB-phoR region of the chromosome, as a multiple copy state of these genes results in the constitutive synthesis of alkaline phosphatase. The presence of multiple copies of the phoM gene hardly influences the level of expression of alkaline phosphatase and PhoE protein in a pho+ strain, but significantly increases the levels of these proteins in a phoR mutant strain.
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