RecA can stimulate the relaxation activity of topoisomerase I: Molecular basis of topoisomerase-mediated genome-wide transcriptional responses in Escherichia coli
Open Access
- 6 December 2006
- journal article
- research article
- Published by Oxford University Press (OUP) in Nucleic Acids Research
- Vol. 35 (1), 79-86
- https://doi.org/10.1093/nar/gkl981
Abstract
The superhelicity of the chromosome, which is controlled by DNA topoisomerases, modulates global gene expression. Investigations of transcriptional responses to the modulation of gyrase function have identified two types of topoisomerase-mediated transcriptional responses: (i) steady-state changes elicited by a mutation in gyrase, such as the D82G mutation in GyrA, and (ii) dynamic changes elicited by the inhibition of gyrase. We hypothesize that the steady-state effects are due to the changes in biochemical properties of gyrase, whereas the dynamic effects are due to an imbalance between supercoiling and relaxation activities, which appears to be influenced by the RecA activity. Herein, we present biochemical evidence for hypothesized mechanisms. GyrA D82G gyrase exhibits a reduced supercoiling activity. The RecA protein can influence the balance between supercoiling and relaxation activities either by interfering with the activity of DNA gyrase or by facilitating the relaxation reaction. RecA has no effect on the supercoiling activity of gyrase but stimulates the relaxation activity of topoisomerase I. This stimulation is specific and requires formation of an active RecA filament. These results suggest that the functional interaction between RecA and topoisomerase I is responsible for RecA-mediated modulation of the relaxation-dependent transcriptional activity of the Escherichia coli chromosome.Keywords
This publication has 51 references indexed in Scilit:
- Magnesium Ion-dependent Activation of the RecA Protein Involves the C TerminusPublished by Elsevier BV ,2003
- Replication restart in gyrB Escherichia coli mutantsMolecular Microbiology, 2003
- A Microarray-Based Antibiotic Screen Identifies a Regulatory Role for Supercoiling in the Osmotic Stress Response of Escherichia coliGenome Research, 2003
- RecA Protein Filaments Disassemble in the 5′ to 3′ Direction on Single-stranded DNAPublished by Elsevier BV ,2001
- The Y-Family of DNA PolymerasesMolecular Cell, 2001
- DNA Topoisomerases: Structure, Function, and MechanismAnnual Review of Biochemistry, 2001
- DNA Gyrase-mediated Wrapping of the DNA Strand Is Required for the Replication Fork Arrest by the DNA Gyrase-Quinolone-DNA Ternary ComplexJournal of Biological Chemistry, 2000
- Analysis of topoisomerase function in bacterial replication fork movement: Use of DNA microarraysProceedings of the National Academy of Sciences of the United States of America, 2000
- The importance of repairing stalled replication forksNature, 2000
- Replication of pBR322 DNA in vitro with purified proteins. Requirement for topoisomerase I in the maintenance of template specificity.Journal of Biological Chemistry, 1985