Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
2011-8-12
pubmed:abstractText
Chlamydia trachomatis is an obligate intracellular bacterium that is dependent on its host cell for nucleotides. Chlamydia imports ribonucleotide triphosphates (NTPs) but not deoxyribonucleotide triphosphates (dNTPs) and instead uses ribonucleotide reductase to convert imported ribonucleotides into deoxyribonucleotides for DNA synthesis. The genes encoding ribonucleotide reductase have been recently shown to be negatively controlled by a conserved regulator called NrdR. In this study, we provide direct evidence that Escherichia coli NrdR is a transcriptional repressor and that C. trachomatis CT406 encodes its chlamydial ortholog. We showed that CT406 binds specifically to two NrdR boxes upstream of the nrdAB operon in C. trachomatis. Using an in vitro transcription assay, we confirmed that these NrdR boxes function as an operator since they were necessary and sufficient for CT406-mediated repression. We validated our in vitro findings with reporter studies in E. coli showing that both E. coli NrdR and CT406 repressed transcription from the E. coli nrdH and C. trachomatis nrdAB promoters in vivo. This in vivo repression was reversed by hydroxyurea treatment. Since hydroxyurea inhibits ribonucleotide reductase and reduces intracellular deoxyribonucleotide levels, these results suggest that NrdR activity is modulated by a deoxyribonucleotide corepressor.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1098-5530
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
193
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4396-404
pubmed:meshHeading
pubmed-meshheading:21725017-Bacterial Proteins, pubmed-meshheading:21725017-Base Sequence, pubmed-meshheading:21725017-Chlamydia trachomatis, pubmed-meshheading:21725017-Chromosome Mapping, pubmed-meshheading:21725017-DNA, Bacterial, pubmed-meshheading:21725017-DNA Replication, pubmed-meshheading:21725017-Deoxyribonucleotides, pubmed-meshheading:21725017-Escherichia coli, pubmed-meshheading:21725017-Escherichia coli Proteins, pubmed-meshheading:21725017-Gene Expression Regulation, Bacterial, pubmed-meshheading:21725017-Genes, Bacterial, pubmed-meshheading:21725017-Hydroxyurea, pubmed-meshheading:21725017-Molecular Sequence Data, pubmed-meshheading:21725017-Operon, pubmed-meshheading:21725017-Plasmids, pubmed-meshheading:21725017-Repressor Proteins, pubmed-meshheading:21725017-Ribonucleotide Reductases, pubmed-meshheading:21725017-Transcription, Genetic
pubmed:year
2011
pubmed:articleTitle
CT406 encodes a chlamydial ortholog of NrdR, a repressor of ribonucleotide reductase.
pubmed:affiliation
Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA 92697-4025, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural