Linked Life Data

10718332

Source:http://linkedlifedata.com/resource/pubmed/id/10718332

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2000-3-31
pubmed:abstractText
To study the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on nuclear protein phosphorylation activities, male guinea pigs were treated in vivo with a single 1 microg/kg i.p. injection of TCDD, and the state of protein kinases and phosphatases in the nuclei of the hepatocytes was examined after 1, 10, and 40 days. TCDD was found to cause a rise in nuclear protein tyrosine kinase on day 1, and to a lesser extent on day 10, but this effect diminished almost completely on day 40. TCDD also caused a reduction in nuclear casein kinase II (CKII) activity at all time points. To study the biochemical events taking place at the early stage of the action of TCDD, a short-term in vitro model system was established using explant liver tissues maintained in tissue culture medium. It was found that TCDD caused a rapid reduction of the activity of nuclear CKII with an accompanying increase in the cytosol. Such changes in protein phosphorylation activities were also accompanied by an increase in the DNA binding activity of activator protein 1 (AP-1). The effect of TCDD on nuclear proteins binding to the c-Myc response element DNA was, on the other hand, biphasic: an initial increase of protein binding to the c-Myc response element was followed by suppression. To test the hypothesis that some of the above changes were caused by TCDD-induced changes in protein kinase activity, nuclear proteins isolated from hepatocytes of in vivo treated guinea pigs were incubated with exogenously added Mg2+ and ATP under cell-free conditions. The results showed that this in vitro phosphorylation treatment exacerbated this tendency of increased AP-1 and decreased c-Myc binding to their respective response element DNAs, indicating that kinases and phosphatases present in the isolated nuclear protein preparation were active and capable of modifying protein binding to DNA. Such effects of Mg2+ and ATP on AP-1 were blocked by heparin, indicating that CKII plays an important role in transducing the signal of TCDD into the nucleus.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2952
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
59
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
741-51
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-induced changes in activities of nuclear protein kinases and phosphatases affecting DNA binding activity of c-Myc and AP-1 in the livers of guinea pigs.
pubmed:affiliation
Department of Environmental Toxicology and Institute of Toxicology and Environmental Health, University of California, Davis 95616, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.