Linked Life Data

7476966

Source:http://linkedlifedata.com/resource/pubmed/id/7476966

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1995-12-12
pubmed:abstractText
Mouse T lymphoma cell line W7MG1, which is killed by physiological concentrations of glucocorticoid agonists, was used as a convenient genetic system for isolating sublines containing mutant glucocorticoid receptors (GR) with hormone-binding deficiencies. Partially hormone-resistant cell clones were derived from chemically mutagenized cell populations by selecting for growth in moderate concentrations of dexamethasone (Dex) and then screening for failure to grow in high Dex concentrations. Such clones are likely to have mutant GR. In GR cDNA clones from the partially resistant cell sublines, three different functionally significant mutations in the hormone-binding domain were identified: Leu-569 changed to Phe (L569F), Leu-670 to Phe (L670F), and Met-672 to Ile (M672I). Dose-response analyses with Dex and affinity labeling studies with dexamethasone 21-mesylate in transiently transfected cells indicated that all three mutant GR species had hormone-binding deficiencies. However, at saturating Dex concentrations the mutant and wild type GR activated a hormone-inducible reporter gene to the same extent; thus, these three mutations did not affect the ability of GR to activate transcription of the reporter gene after hormone was bound. In dose-response curves conducted with several glucocorticoid agonists, mutations L670F and M672I caused no change in ligand-binding specificities, while mutation L569F caused a modest change in specificity. Quantitative hormone-binding studies conducted with mutant GR synthesized in cell-free reactions showed that mutant GR species L569F and M672I had reduced Dex-binding affinities both at 0 C and at 22 C in the presence of molybdate. In contrast, for the L670F mutant, which exhibited the severest deficiency in vivo, the hormone-binding deficiency in the cell-free system was evident only at 26-37 C and primarily in the absence of molybdate. We propose that the L670F GR is an activation-labile type of mutant, which binds hormone normally in the presence of heat shock protein 90 but loses hormone rapidly after dissociation from heat shock protein 90. These three mutations define two new subregions of the GR polypeptide that are important for hormone binding.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0888-8809
pubmed:author
pubmed:issnType
Print
pubmed:volume
9
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
826-37
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
A somatic cell genetic method for identification of untargeted mutations in the glucocorticoid receptor that cause hormone binding deficiencies.
pubmed:affiliation
Department of Pathology, University of Southern California Health Sciences Campus, Los Angeles 90033, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.