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Mutant DnaAs of Escherichia coli that are refractory to negative control
- Source :
- Nucleic Acids Research
- Publication Year :
- 2013
-
Abstract
- DnaA is the initiator of DNA replication in bacteria. A mutant DnaA named DnaAcos is unusual because it is refractory to negative regulation. We developed a genetic method to isolate other mutant DnaAs that circumvent regulation to extend our understanding of mechanisms that control replication initiation. Like DnaAcos, one mutant bearing a tyrosine substitution for histidine 202 (H202Y) withstands the regulation exerted by datA, hda and dnaN (β clamp), and both DnaAcos and H202Y resist inhibition by the Hda-β clamp complex in vitro. Other mutant DnaAs carrying G79D, E244K, V303M or E445K substitutions are either only partially sensitive or refractory to inhibition by the Hda-β clamp complex in vitro but are responsive to hda expression in vivo. All mutant DnaAs remain able to interact directly with Hda. Of interest, both DnaAcos and DnaAE244K bind more avidly to Hda. These mutants, by sequestrating Hda, may limit its availability to regulate other DnaA molecules, which remain active to induce extra rounds of DNA replication. Other evidence suggests that a mutant bearing a V292M substitution hyperinitiates by escaping the effect of an unknown regulatory factor. Together, our results provide new insight into the mechanisms that regulate replication initiation in Escherichia coli.
- Subjects :
- DNA Replication
DNA polymerase
Mutant
dnaN
Replication Origin
DNA-Directed DNA Polymerase
Genome Integrity, Repair and Replication
medicine.disease_cause
Plasmid
Bacterial Proteins
Genetics
medicine
Alleles
DNA Polymerase III
Adenosine Triphosphatases
Mutation
biology
Escherichia coli Proteins
DNA replication
DnaA
DNA-Binding Proteins
Biochemistry
Replication Initiation
biology.protein
bacteria
Subjects
Details
- ISSN :
- 13624962
- Volume :
- 41
- Issue :
- 22
- Database :
- OpenAIRE
- Journal :
- Nucleic acids research
- Accession number :
- edsair.doi.dedup.....f6239d3c953f5f854f593b7957efd3ae