Linked Life Data

7438052

Source:http://linkedlifedata.com/resource/pubmed/id/7438052

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1981-2-26
pubmed:abstractText
The effects of steroid-induced modifications of chromatin structure on the extent and sites of chloroethylnitrosourea binding to chromatin were studied using log-phase HeLa cells. The cells were exposed to 0.1 to 2.0 microM hydrocortisone for 22 hr; this resulted in depressed DNA synthesis while transcriptional activity was stimulated. Hydrocortisone had no effect upon cellular or nuclear uptake of the two nitrosoureas under study, 0.6 mM chlorozotocin or 1-(2-chloroethyl-3-cyclohexyl-1-nitrosourea). Both drugs were found to alkylate transcriptional chromatin preferentially, as demonstrated by DNase II and DNase I digestion. This alkylation was stimulated 2-fold by the same micromolar concentrations of hydrocortisone, 0.1 to 2.0 microM, which stimulated transcription. The extent of nuclear RNA alkylation, determined using RNase T2 as a probe, was found to contribute less than 20% of total chromatin alkylation and was unaffected by steroid pretreatment. Instead, the increased alkylation within these chromatin subfractions was attributed to a steroid-induced alteration of chromatin structure. Electron microscopic examination of HeLa nuclear morphology revealed a hydrocortisone-induced disaggregation of nuclear membrane-associated heterochromatin resulting in a more heterogeneous, less condensed distribution of chromatin. Such data are consistent with a relaxation of the supercoiled chromatin structure, resulting in increased transcription and increased accessibility of potential target sites for nitrosourea alkylation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3697-3703
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1980
pubmed:articleTitle
Influence of hydrocortisone on the binding of nitrosoureas to nuclear chromatin subfractions.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't