The structure of the E beta gene is more similar to class I MHC genes than to class II, in that, unlike either the E alpha or DR alpha genes, (1) the core portion of the E beta cytoplasmic segment is encoded by its own exon and (2) the sixth exon of the E beta chain is not split into two exons, but rather encodes both the carboxyl end of the cytoplasmic segment and the entire 3'-UTR. Belongs to the MHC class II family.