In Escherichia coli, yeast and mammalian cells, the genes encoding ribonucleotide reductase, an essential enzyme for de novo DNA synthesis, are up-regulated in response to DNA damaging agents. We have examined the response of the rnrB gene, encoding the small subunit of ribonucleotide reductase in Dictyostelium discoideum, to DNA damaging agents. We show here that the accumulation of rnrB trans...

Infection of shrimp cells with white spot syndrome virus (WSSV) results in an increase in ribonucleotide reductase (RR) expression at the RNA level. In this article we further express and characterize the induction of a novel ribonucleotide reductase after WSSV infection of shrimp cells. A baculovirus/insect system was used to express the two recombinant protein subunits RR1 and RR2, and a DNA ...

Percutaneous transluminal coronary angioplasty (PTCA) has greatly benefited patients with occluded coronary arteries, but its benefits have been undermined by a high incidence of restenosis. The introduction of coronary stents has significantly improved the short and long term outcome but restenosis still occurs in approximately 15 to 30% of patients within 6 months. Research efforts are now be...

Campylobacter jejuni is a small genome pathogen that is incapable of growing strictly anaerobically due to its dependence on an oxygen-requiring ribonucleotide reductase for DNA synthesis. Nevertheless, it has a complex branched respiratory chain, which allows the use of several alternative electron acceptors for growth under oxygen-limited conditions. C. jejuni is equipped with both nitrate re...

Curcumin, a naturally occurring polyphenolic compound, is known to possess diverse pharmacological properties. There is a scarcity of literature documenting the exact mechanism by which curcumin modulates its biological effects. In the present study, we have used yeast as a model organism to dissect the mechanism underlying the action of curcumin. We found that the yeast mutants of histone prot...

In many organisms, hydroxyurea (HU) inhibits class I ribonucleotide reductase, leading to lowered cellular pools of deoxyribonucleoside triphosphates. The reduced levels for DNA precursors is believed to cause replication fork stalling. Upon treatment of the hyperthermophilic archaeon Sulfolobus solfataricus with HU, we observe dose-dependent cell cycle arrest, accumulation of DNA double-strand...

Using comparative genomics approaches, we analyzed the regulation of ribonucleotide reductase genes in bacterial genomes. A highly conserved palindromic signal with consensus acaCwAtATaTwGtg, named NrdR-box, was identified upstream of most operons encoding ribonuleotide reductases from three different classes. By correlating the occurrence of NrdR-boxes with phylogenetic distribution of ortholo...

Mouse fibroblast 3T6 cells, selected for resistance to hydroxyurea, were shown to overproduce protein M2, one of the two nonidentical subunits of mammalian ribonucleotide reductase. Packed resistant cells gave an EPR signal at 77 K very much resembling the signal given by the tyrosine-free radical of the B2 subunit of Escherichia coli ribonucleotide reductase. Also, the M2-specific free radical...