Nuclear and mitochondrial (mt) DNA replication occur within two physically separated compartments and on different time scales. Both require a balanced supply of dNTPs. During S phase, dNTPs for nuclear DNA are synthesized de novo from ribonucleotides and by salvage of thymidine in the cytosol. Mitochondria contain specific kinases for salvage of deoxyribonucleosides that may provide a compartm...

The phosphorylations of thymidine-3H and deox-yuridine-3H (thymidine kinase activity) were markedly enhanced in primary cultures of murine cells 16—48hr after polyoma virus infection. The presence of puromycin in the infected cultures from 18 to 28 hr after infection l)revented this increase. If purornycin was removed at 28 hr, thymidine kinase synthesis was restored. Addition of 1-/3-n-arabi...

WK, hen the epithelial cells of the cornea of the dogfish are mechanically injured, a rapid incorporation of tritium-labeled thymidine (H3 thymidine) into deoxyribonucleic acid (DNA) takes place. Incubation in vitro of conical epithelial cells of the dogfish also demonstrates a significant degree of incorporation of thymidine into DNA. The depression of thymidine uptake when the temperature is ...

Chromatin from Friend leukemia cells labeled with [14C]thymidine for 24 hr followed by [3H]thymidine for 10 min is converted into nucleosomes by staphylococcal nuclease at only half the rate that total chromatin is converted. Polyacrylamide gel electrophoresis of nucleosomal DNA from cells labeled for 24 hr with [14C]thymidine followed by 10 min with [3H]thymidine demonstrates that the internuc...

The uptake of thymidine into an acid-soluble pool in normal hamster embryo cells and hamster tumor cells transformed by polyoma virus was studied. It was found that tumor cells exhibited a 4-fold higher capacity than normal cells to incorporate thymidine as phosphorylated products into this pool. This was correlated with a 5to 10-fold higher activity of thymidine kinase in the tumor cell lines....

of bone marrow cells from untreated rabbits. The factor responsible for the decreased uptake was found to be dialyzable and, on paper chromatography in 4 different solvent systems, had the same RF values as did thymidine. Serial dilutions of this factor gave a dose-related response in the bone marrow suspensions that was identical to that obtained with thymidine, 0.01 to 0.25 ¿ig/ml,confirming...

Human mononuclear cells were exposed to three antiviral agents, stimulated with phytohemagglutinin, and assayed for DNA synthesis with [3H]thymidine uptake and flow cytometric analysis. Cytosine-arabinoside demonstrated inhibition of blastogenic reactivity by both [3H]thymidine uptake and flow cytometric analysis, whereas acyclovir showed no significant suppression. In contrast, (E)-5-(2-bromov...

Cytosolic thymidine kinase (EC 2.7.1.21) has been purified 5200-fold to apparent homogeneity from normal human placenta. The purification includes sequential affinity chromatography on blue-Sepharose and a thymidine column. The molecular weight of the enzyme determined by gel filtration and sucrose density ultracentrifugation is 92,000. The subunit molecular weight is 44,000, suggesting that t...

Dengue virus has emerged as a global health threat to over one-third of humankind. As a positive-strand RNA virus, dengue virus relies on the host cell metabolism for its translation, replication, and egress. Therefore, a better understanding of the host cell metabolic pathways required for dengue virus infection offers the opportunity to develop new approaches for therapeutic intervention. In ...

The cell line LM(TK(-)) Cl 1D, a derivative of mouse L fibroblasts deficient in thymidine kinase (EC 2.7.1.21) that shows very little thymidine kinase activity in extracts of whole cells as compared to the parental line, and that does not incorporate thymidine or 5-bromodeoxyuridine into nuclear DNA, has maintained the capacity to incorporate these precursors into mitochondrial DNA at a substan...