Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
50
pubmed:dateCreated
2003-12-8
pubmed:abstractText
Deoxycytidine kinase (EC 2.7.1.74, dCK) is central to drug activity of anticancer and antiviral agents such as cytosine arabinoside (araC) and gemcitabine. HepG2 hepatocellular carcinoma cells were used to study the transcriptional regulation of dCK. 5'-Deletion and site-directed mutagenesis of the dCK upstream region (positions -464 to -27) confirmed the importance of two GC-boxes (positions -317 to -309 and -213 to -206) and two E-boxes (positions -302 to -297 and -278 to -273). In vitro electromobility shift assays with HepG2 nuclear extracts and in vivo chromatin immunoprecipitation assays with HepG2 chromatin extracts confirmed the presence of bound Sp1/Sp3 and USF1/2. Co-transfections in HepG2 cells showed that USF1 and USF2a stimulated and Sp1 repressed promoter activity from a dCK-luciferase reporter gene construct. In Sp- and USF-null Drosophila Mel-2 cells, both Sp1 and USF1 stimulated dCK promoter activity in a dose-dependent manner, however, both Sp3 and USF2a were effectively inert. Combined Sp1 and USF1 showed additive transactivation at lower concentrations of Sp1. Sp1 was inhibitory at higher levels. Stimulation by combined USF1/USF2a with Sp1 was similar to that for USF1 alone with Sp1, whereas transactivation by Sp1 and USF2a without USF1 was synergistic. Physical interactions between USF and Sp proteins were confirmed by immunoprecipitations with Sp- and USF-specific antibodies. Domain mapping of USF1 and USF2a localized the functional interactions between USF and Sp proteins to the DNA binding domain of USF. Identifying the physical and functional interactions between Sp and USF proteins may lead to a better understanding of the basis for differential expression of the dCK gene in tumor cells and may foster strategies for up-regulating dCK gene expression and improving chemotherapy with araC and gemcitabine.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
49901-10
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:14514691-Animals, pubmed-meshheading:14514691-Antimetabolites, Antineoplastic, pubmed-meshheading:14514691-Base Sequence, pubmed-meshheading:14514691-Blotting, Western, pubmed-meshheading:14514691-Cell Line, pubmed-meshheading:14514691-Cell Line, Tumor, pubmed-meshheading:14514691-Cell Nucleus, pubmed-meshheading:14514691-Chromatin, pubmed-meshheading:14514691-Cytarabine, pubmed-meshheading:14514691-DNA-Binding Proteins, pubmed-meshheading:14514691-Deoxycytidine, pubmed-meshheading:14514691-Deoxycytidine Kinase, pubmed-meshheading:14514691-Drosophila, pubmed-meshheading:14514691-Gene Deletion, pubmed-meshheading:14514691-Gene Expression Regulation, Enzymologic, pubmed-meshheading:14514691-Humans, pubmed-meshheading:14514691-Molecular Sequence Data, pubmed-meshheading:14514691-Mutagenesis, Site-Directed, pubmed-meshheading:14514691-Plasmids, pubmed-meshheading:14514691-Precipitin Tests, pubmed-meshheading:14514691-Promoter Regions, Genetic, pubmed-meshheading:14514691-Protein Binding, pubmed-meshheading:14514691-Protein Structure, Tertiary, pubmed-meshheading:14514691-Sp1 Transcription Factor, pubmed-meshheading:14514691-Transcription Factors, pubmed-meshheading:14514691-Transfection, pubmed-meshheading:14514691-Upstream Stimulatory Factors
pubmed:year
2003
pubmed:articleTitle
Physical and functional interactions between USF and Sp1 proteins regulate human deoxycytidine kinase promoter activity.
pubmed:affiliation
Experimental and Clinical Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Detroit, Michigan 48201, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't