Linked Life Data

10481032

Source:http://linkedlifedata.com/resource/pubmed/id/10481032

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
1999-12-17
pubmed:abstractText
Ribosomal DNA (rDNA) replication origins of Saccharomyces cerevisiae are known to function inefficiently, both in the context of the tandem rDNA repeats in the chromosome and as single copy autonomously replicating sequences (ARSs) in plasmids. Here we examined components of the rDNA ARS that might contribute to inefficient extrachromosomal replication. Like the efficient H4 ARS, the rDNA ARS requires a match to the 11 bp ARS consensus sequence (ACS) and a broad non-conserved region that may contain multiple elements, including a DNA unwinding element (DUE). Using a single-strand-specific nuclease hypersensitivity assay and by determining the superhelical density required for stable DNA unwinding, we found that the DNA of the rDNA ARS is not as easily unwound as the H4 ARS. Unwinding of the rDNA ARS required additional energy, similar to the unwinding of mutations in the H4 ARS that stabilize the double helix in the DUE region and impair replication. In vivo extrachromosomal replication of the rDNA ARS was cold sensitive, like H4 ARS mutants that require additional energy to unwind the DUE region but unlike the easily unwound, wild-type H4 ARS. Impairment of replication function at reduced temperature suggests that the elevated energy requirement for DNA unwinding inherent in the wild-type rDNA ARS contributes to inefficient replication function. We also examined the essential ACS match in the rDNA ARS, which is known to be imperfect at one position. A point mutation in the essential ACS that corrects the imperfect match increased the efficiency of extrachromosomal replication. Our results reveal that the essential ACS element and DNA unwinding in the rDNA ARS are naturally impaired, suggesting that inefficient function of the rDNA replication origin has a biological purpose.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1362-4962
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3921-30
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
The inefficient replication origin from yeast ribosomal DNA is naturally impaired in the ARS consensus sequence and in DNA unwinding.
pubmed:affiliation
Cancer Genetics Department, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.