Linked Life Data

8898232

Source:http://linkedlifedata.com/resource/pubmed/id/8898232

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1996-12-10
pubmed:abstractText
It has been a controversial issue as to how many DNA cytosine methyltransferase mammalian cells have and whether de novo methylation and maintenance methylation activities are encoded by a single gene or two different genes. To address these questions, we have generated a null mutation of the only known mammalian DNA methyltransferase gene through homologous recombination in mouse embryonic stem cells and found that the development of the homozygous embryos is arrested prior to the 8-somite stage. Surprisingly, the null mutant embryonic stem cells are viable and contain low but stable levels of methyl cytosine and methyltransferase activity, suggesting the existence of a second DNA methyltransferase in mammalian cells. Further studies indicate that de novo methylation activity is not impaired by the mutation as integrated provirus DNA in MoMuLV-infected homozygous embryonic stem cells become methylated at a similar rate as in wild-type cells. Differentiation of mutant cells results in further reduction of methyl cytosine levels, consistent with the de novo methylation activity being down regulated in differentiated cells. These results provide the first evidence that an independently encoded DNA methyltransferase is present in mammalian cells which is capable of de novo methylating cellular and viral DNA in vivo.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0950-1991
pubmed:author
pubmed:issnType
Print
pubmed:volume
122
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3195-205
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
De novo DNA cytosine methyltransferase activities in mouse embryonic stem cells.
pubmed:affiliation
Cardiovascular Research Center, Massachusetts General Hospital-East, Charlestown 02129, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't