Linked Life Data

12499119

Source:http://linkedlifedata.com/resource/pubmed/id/12499119

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
2002-12-24
pubmed:abstractText
This study demonstrates that in vitro exposure of adult rat alveolar epithelial cells to CdCl(2) decreases DNA binding activity of specificity protein 1 (Sp1), a zinc-finger transcription factor known to play a key role in eukaryotic gene expression, maintenance of homeostasis, cell cycle control, terminal differentiation, and apoptosis. Suppression of Sp1 function, as assessed by electrophoretic mobility shift assays (EMSAs), is dependent upon cadmium (Cd) dose and duration of exposure. A 45% decrease of Sp1 activity occurs as early as 30 min after Cd addition. By 2 h, Sp1 activity is reduced even further with no loss of cell viability, suggesting that Sp1 inactivation precedes cell death. If Cd is removed from cultures during these early periods of exposure, inhibition of Sp1 binding activity is reversed. Sp1 inactivation does not appear to be a generalized, non-selective response to Cd as other transcription factors are up-regulated under the same conditions. Phosphorylation is involved in Sp1 down-regulation, as evidenced by the finding that alkaline phosphatase treatment of nuclear extracts from cells exposed to Cd for 2 h helps restore Sp1 binding activity. A broad spectrum Protein Kinase C (PKC) inhibitor, GF109203X, substantially reduces the Cd-mediated effect on Sp1 suggesting that a member of the PKC family is required for Sp1 phosphorylation. More prolonged Cd exposure promotes Sp1 degradation with the appearance of cleavage products (40 and 50 kDa), as detected by Western blotting. Changes in the integrity of the Sp1 protein are accompanied by a corresponding decline in cell survival. Cd-induced cell death is substantially attenuated if cells are pretreated with antagonists of PKC activity which implies that a PKC isoform is also a participant in this process.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0300-483X
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
184
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
157-78
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:12499119-Animals, pubmed-meshheading:12499119-Apoptosis, pubmed-meshheading:12499119-Blotting, Western, pubmed-meshheading:12499119-Cadmium, pubmed-meshheading:12499119-Cadmium Radioisotopes, pubmed-meshheading:12499119-Cell Line, pubmed-meshheading:12499119-Cell Nucleus, pubmed-meshheading:12499119-Culture Media, pubmed-meshheading:12499119-Dose-Response Relationship, Drug, pubmed-meshheading:12499119-Down-Regulation, pubmed-meshheading:12499119-Electrophoretic Mobility Shift Assay, pubmed-meshheading:12499119-Enzyme-Linked Immunosorbent Assay, pubmed-meshheading:12499119-Epithelial Cells, pubmed-meshheading:12499119-Nuclear Proteins, pubmed-meshheading:12499119-Oxidation-Reduction, pubmed-meshheading:12499119-Phosphorylation, pubmed-meshheading:12499119-Protein Kinase C, pubmed-meshheading:12499119-Proteins, pubmed-meshheading:12499119-Pulmonary Alveoli, pubmed-meshheading:12499119-RNA, Messenger, pubmed-meshheading:12499119-Rats, pubmed-meshheading:12499119-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:12499119-Sp1 Transcription Factor, pubmed-meshheading:12499119-Tetrazolium Salts, pubmed-meshheading:12499119-Thiazoles, pubmed-meshheading:12499119-Time Factors
pubmed:year
2003
pubmed:articleTitle
Mechanisms regulating the cadmium-mediated suppression of Sp1 transcription factor activity in alveolar epithelial cells.
pubmed:affiliation
Department of Biochemistry, University of Vermont College of Medicine, Burlington, VT 05405-0068, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.