Fig. 2.

Schematic diagram of the UBE3A gene showing exons 1–16 and 3 of the most studied protein isoforms that differ by 20 and 23 amino acids at the amino terminal aspect. Exons 9–16 constitute the HECT binding and transfer domains. The steroid coactivation region does occupy a contiguous genomic region but spans a region that contains several 5-amino acid motifs known to be receptor interacting motifs [Ramamoorthy and Nawaz, 2008]. An alternative exon numbering system for UBE3A is indicated by the asterisk, as designated by Yamamoto et al. [1997].