CpG islands are distinguishable from the bulk of vertebrate DNA for being unmethylated and CpG-rich. Since CpG doublets are the specific target of eukaryotic DNA methyltransferases, CpG-rich sequences might be expected to be good methyl-accepting substrates in vitro, despite their unmethylated in vivo condition. This was tested using a partially purified DNA-methyltransferase from human placenta and several cloned CpG-rich or CpG-depleted sequences. The efficiency of methylation was found to be proportional to the CpG content for CpG-depleted regions, which are representative of the bulk genome. However, methylation was much less efficient for CpG frequencies higher than 1 in 12 nucleotides, reaching only 60% of the expected level. That suggests that the close CpG spacing typical of CpG-islands somehow inhibits mammalian DNA methyltransferase. The implications of these findings on the in vivo pattern of DNA methylation are discussed.
In vitro methylation of CpG-rich islands / Carotti, Daniela; Palitti, Franco; Lavia, P; Strom, Roberto. - In: NUCLEIC ACIDS RESEARCH. - ISSN 0305-1048. - STAMPA. - 17:22(1989), pp. 9219-9229. [10.1093/nar/17.22.9219]
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|Titolo:||In vitro methylation of CpG-rich islands.|
|Data di pubblicazione:||1989|
|Citazione:||In vitro methylation of CpG-rich islands / Carotti, Daniela; Palitti, Franco; Lavia, P; Strom, Roberto. - In: NUCLEIC ACIDS RESEARCH. - ISSN 0305-1048. - STAMPA. - 17:22(1989), pp. 9219-9229. [10.1093/nar/17.22.9219]|
|Appartiene alla tipologia:||01a Articolo in rivista|