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An unusual S-adenosylmethionine synthetase gene from dinoflagellate is methylated.
- Source :
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BMC molecular biology [BMC Mol Biol] 2007 Oct 04; Vol. 8, pp. 87. Date of Electronic Publication: 2007 Oct 04. - Publication Year :
- 2007
-
Abstract
- Background: S-Adenosylmethionine synthetase (AdoMetS) catalyzes the formation of S-Adenosylmethionine (AdoMet), the major methyl group donor in cells. AdoMet-mediated methylation of DNA is known to have regulatory effects on DNA transcription and chromosome structure. Transcription of environmental-responsive genes was demonstrated to be mediated via DNA methylation in dinoflagellates.<br />Results: A full-length cDNA encoding AdoMetS was cloned from the dinoflagellate Crypthecodinium cohnii. Phylogenetic analysis suggests that the CcAdoMetS gene, is associated with the clade of higher plant orthrologues, and not to the clade of the animal orthrologues. Surprisingly, three extra stretches of residues (8 to 19 amino acids) were found on CcAdoMetS, when compared to other members of this usually conserved protein family. Modeled on the bacterial AdeMetS, two of the extra loops are located close to the methionine binding site. Despite this, the CcAdoMetS was able to rescue the corresponding mutant of budding yeast. Southern analysis, coupled with methylation-sensitive and insensitive enzyme digestion of C. cohnii genomic DNA, demonstrated that the AdoMetS gene is itself methylated. The increase in digestibility of methylation-sensitive enzymes on AdoMet synthetase gene observed following the addition of DNA methylation inhibitors L-ethionine and 5-azacytidine suggests the presence of cytosine methylation sites within CcAdoMetS gene. During the cell cycle, both the transcript and protein levels of CcAdoMetS peaked at the G1 phase. L-ethionine was able to delay the cell cycle at the entry of S phase. A cell cycle delay at the exit of G2/M phase was induced by 5-azacytidine.<br />Conclusion: The present study demonstrates a major role of AdoMet-mediated DNA methylation in the regulation of cell proliferation and that the CcAdoMetS gene is itself methylated.
- Subjects :
- Animals
Antimetabolites pharmacology
Bacteria enzymology
Bacteria genetics
Bacterial Proteins genetics
Bacterial Proteins metabolism
Cell Division drug effects
DNA, Complementary genetics
DNA, Complementary metabolism
DNA, Protozoan metabolism
Dinoflagellida enzymology
Ethionine pharmacology
Fungal Proteins genetics
Fungal Proteins metabolism
G2 Phase drug effects
Methionine Adenosyltransferase metabolism
Models, Molecular
Phylogeny
Plant Development
Plant Proteins genetics
Plant Proteins metabolism
Plants enzymology
Plants genetics
Protozoan Proteins genetics
Protozoan Proteins metabolism
Saccharomycetales enzymology
Saccharomycetales genetics
Cell Division physiology
DNA Methylation drug effects
DNA, Protozoan genetics
Dinoflagellida genetics
G2 Phase physiology
Methionine Adenosyltransferase genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1471-2199
- Volume :
- 8
- Database :
- MEDLINE
- Journal :
- BMC molecular biology
- Publication Type :
- Academic Journal
- Accession number :
- 17915037
- Full Text :
- https://doi.org/10.1186/1471-2199-8-87