Linked Life Data

11919202

Source:http://linkedlifedata.com/resource/pubmed/id/11919202

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
2002-6-3
pubmed:abstractText
The C-terminal domains of the mammalian DNA methyltransferases Dnmt1, Dnmt3a, and Dnmt3b harbor all the conserved motifs characteristic for cytosine-C5 methyltransferases. Whereas the isolated catalytic domain of Dnmt1 is inactive, we show here that the C-terminal domains of Dnmt3a and Dnmt3b are catalytically active. Neither Dnmt3a nor Dnmt3b shows a significant preference for the satellite 2 sequence, although Dnmt3b is required for methylation of these regions in vivo. However, the catalytic domain of Dnmt3a methylates DNA in a distributive reaction, whereas Dnmt3b is processive, which accelerates methylation of macromolecular DNA in vitro. This property could make Dnmt3b a preferred enzyme for methylation at satellite 2 repeats, since they are highly CG-rich. We have also analyzed the catalytic activities of six different mutations found in ICF (immunodeficiency, centromeric instability, and facial abnormalities) patients in the catalytic domain of Dnmt3b. Five of them display catalytic activities reduced by 10-50-fold; one mutant was inactive in our assay (residual activity <1%). These results confirm that a reduced catalytic activity of Dnm3b causes ICF. However, the mutations in general do not completely abrogate catalytic activity. This finding may explain why ICF patients are viable, whereas nmt3b knock-out mice die during embryogenesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
20409-14
pubmed:dateRevised
2010-5-21
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Molecular enzymology of the catalytic domains of the Dnmt3a and Dnmt3b DNA methyltransferases.
pubmed:affiliation
Institut für Biochemie, FB 8, Justus-Liebig-Universität, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't