Mouse and Xenopus tropicalis DOT1L proteins are highly conserved. (A) Schematic alignment of mouse and Xenopus tropicalis DOT1L. The gray boxes represent conserved domains for S-adenosylmethionine (AdoMet or SAM)-dependent methyltransferases (AdoMet-MTases). The black boxes indicate structural maintenance of chromosome (SMC) domains. GenBank accession numbers: Mouse (m; Mus musculus) Dot1a (AAP42293) , Xenopus tropicalis (Xt) Dot1L (XP_002937984). Note that the N-terminal region is highly conserved between mouse and Xenopus tropicalis Dot1L due to the presence of the AdoMet-MTase and SMC domains. (B) The amino acid sequences of the nearly perfectly conserved AdoMet-MTase domain of mouse and Xenopus DOT1L. The AdoMet-binding site, which is essential for the methyltransferase activity, is boxed.