Linked Life Data

7956355

Source:http://linkedlifedata.com/resource/pubmed/id/7956355

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1994-12-2
pubmed:abstractText
After transfection of amplification-promoting DNA elements into mammalian cells, homogeneously staining regions (HSRs) are formed by high copy numbers of transfected DNA arranged in head-to-tail polymers. Here, we wanted to evaluate the stability of this type of HSR during prolonged cultivation of transfected cells in selective medium. Thymidine kinase-deficient mouse L cells were transfected with pAPR4tk DNA harboring the amplification-promoting element 4 (APR4) linked to the gene for thymidine kinase (TK) or, alternatively, transfected with a DNA construct (pARP4t-PA) carrying, in addition, the expression cassette for human tissue-type plasminogen activator (t-PA). After transfection, one or two HSRs per cell were formed that disintegrated spontaneously after 25-40 wk of continuous cultivation in the presence of selective HAT (hypoxanthine-aminopterin-thymidine) medium. Unexpectedly, plasmid DNA reinserted into a plethora of new chromosomal sites, as revealed by in situ hybridization and Southern blot analysis. Coincidently, secretion of t-PA decreased to 10-20% of its original level. After transfection of pAPR4tk DNA lacking the t-PA expression cassette, HSR decay and reintegration of plasmid constructs into multiple chromosomal sites were also observed, whereas the ptk vector without an amplification-promoting DNA element did not form an HSR after transfection. We conclude that, in contrast to the pattern of known structures with head-to-tail arrangements, the HSR formed by amplification-promoting DNA elements represents a novel type of HSR that disintegrates by transposition into a plethora of new chromosomal integration sites. This process is mediated by the amplification-promoting DNA element itself and can be observed even when selective pressure is maintained.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0301-0171
pubmed:author
pubmed:issnType
Print
pubmed:volume
68
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
33-8
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
A novel type of unstable homogeneously staining region with a head-to-tail arrangement: spontaneous decay and reintegration of DNA elements into a plethora of new chromosomal sites.
pubmed:affiliation
Institut für Anthropologie und Humangenetik, Universität München, Germany.
pubmed:publicationType
Journal Article