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Escherichia coli ribonucleotide reductase expression is cell cycle regulated
Molecular Biology of the Cell
|October 1, 1992
Summary
Ribonucleotide reductase gene expression in Escherichia coli is cell cycle-dependent. Its mRNA and protein levels peak during DNA synthesis initiation, demonstrating regulated control.
Area of Science:
- Molecular Biology
- Microbiology
- Genetics
Background:
- Ribonucleotide reductase is essential for DNA synthesis.
- Understanding its regulation is key to cell cycle control.
Purpose of the Study:
- To investigate the cell cycle-dependent expression of ribonucleotide reductase genes (nrd) in Escherichia coli.
- To elucidate the regulatory mechanisms controlling nrd expression.
Main Methods:
- Cell synchronization using sucrose gradient centrifugation and phosphate-limited media.
- Antibody production against the B2 subunit.
- Immunoprecipitation and RNA-DNA dot blot hybridization.
- Construction of a promoter-lacZ fusion system.
Main Results:
- Ribonucleotide reductase activity and DNA initiation increased in parallel during the cell cycle.
- Both nrd-mRNA and B2 subunit expression peaked during DNA synthesis initiation and decreased afterward.
- A promoter-lacZ fusion demonstrated cell cycle-regulated transcription of nrd.
Conclusions:
- Ribonucleotide reductase expression in E. coli is tightly regulated in a cell cycle-dependent manner.
- Transcriptional regulation plays a significant role in controlling nrd expression during the cell cycle.