Zusammenfassung
The Dnmt3a DNA cytosine-C5 methyltransferase has been recently shown to exhibit a complex oligomerization and multimerization potential, the structural basis and functional implications of which will be the subject of this contribution. The enzyme forms a linear heterotetramer with Dnmt3L, in which the interaction of Dnmt3a and 3L stimulates the catalytic activity of Dnmt3a. Isolated Dnmt3a forms protein filaments that bind to several DNA molecules oriented in parallel, which plays an essential role in the location of the enzyme to heterochromatin. Dnmt3L disrupts Dnmt3a protein filaments and leads to a redistribution of the enzyme in cells toward euchromatin. Finally, Dnmt3a complexes and Dnmt3a/3L heterotetramers cooperatively multimerize on DNA forming protein–DNA filaments. This leads to a preference of the enzyme for periodic methylation of DNA and supports its heterochromatic localization.
Nutzer
