JMJD2A encodes a deduced 1,064-amino acid protein. Like JMJD2B and JMJD2C, JMJD2A contains a JmjN domain, a JmjC domain, a JD2H domain, 2 TUDOR domains, and a bipartite nuclear localization signal that overlaps the C-terminal part of the second TUDOR domain. JmjN is a small domain found in the Jumonji family of transcription factors. JmjC is a putative enzymatic domain. JD2H is a region containing 2 cys-his clusters with weak similarity to a PHD domain.This gene is a member of the Jumonji domain 2 (JMJD2) family and encodes a protein containing a JmjN domain, a JmjC domain, a JD2H domain, two TUDOR domains, and two PHD-type zinc fingers. This nuclear protein functions as a trimethylation-specific demethylase, converting specific trimethylated histone residues to the dimethylated form, and as a transcriptional repressor.