rRNA N6-methyltransferase that specifically methylates the adenine in position 4220 of 28S rRNA (PubMed:30531910, PubMed:31328227, PubMed:31799605, PubMed:31695039). N6-methylation of adenine(4220) in 28S rRNA is required for translation (PubMed:30531910, PubMed:31799605). adenosine(4220) in 28S rRNA + S-adenosyl-L-methionine = H(+) + N(6)-methyladenosine(4220) in 28S rRNA + S-adenosyl-L-homocysteine Interacts with components of the ASC-1 complex TRIP4, ASCC1, ASCC2 and ASCC3 (PubMed:31799605). Interact with AHCYL1 and AHCYL2 (PubMed:31799605). Interact with YTHDC2 (PubMed:31799605). Accumulates in the nucleolus, where ribosome biogenesis takes place. The regulatory loop blocks the catalytic center by bridging the methyltransferase domain and the C-terminal CCHC-type zinc finger, resulting in an autoinhibitory conformation. Belongs to the ZCCHC4 family. Truncated N-terminus. Truncated N-terminus.