DNMT3L is a non-catalytic homologue of DNMT3A and DNMT3B which binds unmethylated lysine-4 of histone H3 (H3K4, Ooi et al. 2007) and recruits DNMT3A-isoform2 (germ cell specific) (Chen et al. 2005, Kareta et al. 2006, Ooi et al. 2007) and, to a lesser extent, other isoforms of DNMT3A via an interaction between the C-terminal regions of DNMT3L and DNMT3A (Chen et al. 2005). Furthermore, DNMT3A binds unmodified tails of histone H3 (Otani et al. 2009). DNMT3L and DNMT3A form tetramers (DNMT3L:DNMT3A:DNMT3A:DNMT3L) that bind DNA located in euchromatic regions (Holz-Schietinger et al. 2011, also inferred from mouse). DNMT3A without DNMT3L forms oligomers that are located in heterochromatin.