Histidine Mutants Requiring Adenine: Selection of Mutants with Reduced hisG Expression in SALMONELLA TYPHIMURIUM
AUTOR(ES)
Johnston, H. Mark
RESUMO
A method is described for the selection of Salmonella typhimurium mutants with reduced levels of hisG enzyme activity. This method is based on the fact that the hisG enzyme catalyzes the consumption of ATP in the first step of histidine biosynthesis. Normally, this reaction is closely regulated, both by feedback inhibition and by repression of the operon. However, conditions can be set up that result in the uncontrolled use of adenine in histidine biosynthesis. Cells grown under these conditions become phenotypic adenine auxotrophs. Some revertant clones that no longer require adenine contain mutations in hisG, hisE, or the his-control region. The hisG mutations are of all types (nonsense, frameshift, missense, deletion and leaky types), and they map throughout the hisG gene.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1213934Documentos Relacionados
- Deletions fusing the hisG and hisD genes in Salmonella typhimurium.
- A Refined Map of the hisG Gene of SALMONELLA TYPHIMURIUM
- Regulation of histidine operon does not require hisG enzyme.
- Features of the rho-dependent transcription termination polar element within the hisG cistron of Salmonella typhimurium.
- Salmonella typhimurium hisG46 (R-Utrecht): Possible Use in Screening Mutagens and Carcinogens