sequence of PEBP2-beta PEBB_MOUSE CBF-beta Cbfb Core-binding factor subunit beta IMR:0704173 PEA2 PEA2-beta PEBP2-beta PEBP2b Pebp2 Pebp2b Pebpb2 Polyomavirus enhancer-binding protein 2 beta subunit SL3-3 enhancer factor 1 subunit beta SL3/AKV core-binding factor beta subunit UniProt:Q08024 core binding factor beta molecule_role