Linked Life Data

9195907

Source:http://linkedlifedata.com/resource/pubmed/id/9195907

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
26
pubmed:dateCreated
1997-7-16
pubmed:abstractText
We incorporated 3H-labeled thymidine, deoxycytidine, or cytidine into dNTPs and DNA of exponentially growing CEM cells. G1 and S phase cells were separated by centrifugal elutriation, and the size and specific activity of dNTP pools were determined to study the cell cycle-dependent regulation of specific dNTP synthesizing enzymes in their metabolic context. With [3H]thymidine, we confirm the earlier demonstrated S phase specificity of thymidine kinase. Incorporation of radioactivity from [5-3H]deoxycytidine into dCTP occurred almost exclusively in G1 cells. During S phase, de novo synthesis by ribonucleotide reductase was switched on, resulting in a 70-fold dilution of [3H]dCTP, confirming that ribonucleotide reductase is an S phase-specific enzyme, whereas deoxycytidine kinase is not. [5-3H]Cytidine appeared in dCTP almost to the same extent in G1 as in S phase, despite the S phase specificity of ribonucleotide reductase. During S phase, DNA replication greatly increased the turnover of dCTP, requiring a corresponding increase in ribonucleotide reductase activity. During G1, the enzyme maintained activity to provide dNTPs for DNA repair and mitochondrial DNA synthesis. The poor incorporation of isotope from deoxycytidine into DNA earlier led to the suggestion that the nucleoside is used only for DNA repair (Xu, Y-Z., Peng, H., and Plunkett, W. (1995) J. Biol. Chem. 270, 631-637). The poor phosphorylation of deoxycytidine in S phase provides a better explanation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
27
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
16118-24
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Cell cycle-dependent metabolism of pyrimidine deoxynucleoside triphosphates in CEM cells.
pubmed:affiliation
Department of Biology, University of Padova, Via Trieste 75, 35121 Padova, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't