DnaC inactivation in Escherichia coli K-12 induces the SOS response and expression of nucleotide biosynthesis genes.
Abstract
Initiation of chromosome replication in E. coli requires the DnaA and DnaC proteins and conditionally-lethal dnaA and dnaC mutants are often used to synchronize cell populations. DNA microarrays were used to measure mRNA steady-state levels in initiation-deficient dnaA46 and dnaC2 bacteria at permissive and non-permissive temperatures and their expression profiles were compared to MG1655 wildtype cells. For both mutants there was altered expression of genes involved in nucleotide biosynthesis at the non-permissive temperature. Transcription of the dnaA and dnaC genes was increased at the non-permissive temperature in the respective mutant strains indicating auto-regulation of both genes. Induction of the SOS regulon was observed in dnaC2 cells at 38 degrees C and 42 degrees C. Flow cytometric analysis revealed that dnaC2 mutant cells at non-permissive temperature had completed the early stages of chromosome replication initiation. We suggest that in dnaC2 cells the SOS response is triggered by persistent open-complex formation at oriC and/or by arrested forks that require DnaC for replication restart.
References
The FIS protein binds and bends the origin of chromosomal DNA replication, oriC, of Escherichia coli
Citations
Methods Mentioned
Software Mentioned
Related Concepts
Related Feeds
Bacterial Protein Structures
Bacterial protein structures can expedite the development of novel antibiotics. Here is the latest research on bacterial proteins and the resolution of their structures.