Linked Life Data

6300683

Source:http://linkedlifedata.com/resource/pubmed/id/6300683

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5907
pubmed:dateCreated
1983-5-27
pubmed:abstractText
In eukaryotic cells, each chromosome is divided into several thousand tandemly arranged replicons, each synthesized at a characteristic time during the S period. Although as yet no eukaryotic DNA sequence known for certain to be a eukaryotic chromosomal replication origin has been isolated, electron microscopic and biochemical evidence suggests that eukaryotic DNA synthesis is initiated at specific sites. We have attempted to establish a system in which functional chromosomal origins could be identified in vivo before their isolation by molecular cloning. For this purpose, we have developed a methotrexate-resistant Chinese hamster ovary cell line (CHOC 400) that contains 1,000 copies of a 135-kilobase (kb) early-replicating sequence, and which includes the gene for dihydrofolate reductase (DHFR). We have shown that initiation of DNA synthesis within each repeated unit (amplicon) is restricted to a small subset of restriction fragments at the beginning of the S period, suggesting that these fragments contain or flank origins of DNA synthesis. Here we report molecular cloning and restriction mapping experiments showing that all of these early-labelled fragments (ELFs) are derived from a single locus within each repeated unit. This result implies that synthesis of each amplicon initiates from a single origin of replication at the onset of S, and that an amplicon is formally equivalent to a replicon.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:volume
302
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
439-41
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:articleTitle
Cloning of the initiation region of a mammalian chromosomal replicon.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't