Characterization of a new variant DNA (cytosine-5)-methyltransferase unable to methylate double stranded DNA isolated from the marine annelid worm Chaetopterus variopedatus

The enzyme S-adenosylmethionine-DNA (cytosine-5)-methyltransferase has been identified, first time for invertebrates, in embryos of the marine polycha ete annelid worm Chaetopterus variopedatus. The molecule has been isolated from embryos at 15 h of development, It is a single peptide of about 200 kD a molecular weight, cross-reacting with antibodies against sea urchin DNA m ethyltransferase. The enzymatic properties of the molecule are similar to t hose of Dnmt1 methyltransferases isolated from other organisms, but with th e peculiarity to be unable to make 'de novo' methylation on double stranded DNA, (C) 1999 Federation of European Biochemical Societies.