| We recently demonstrated that RFP , which belongs to the large B box RING finger protein family , interacts with Enhancer of Polycomb 1 ( EPC 1 ) and functions as a transcriptional repressor in human cultured cells . ^^^ In this study , we examined the expression of RFP and EPC 1 in mouse tissues by immunoblotting as well as their interaction by a pull down assay . ^^^ Both RFP and EPC 1 proteins are expressed in several mouse tissues including testis , spleen , thymus , adrenal gland , cerebrum , and cerebellum . ^^^ Pull down assays using glutathione S transferase ( GST ) fused EPC 1 proteins revealed that RFP is associated with the EPcA , EPcB , and carboxy terminal ( CT ) regions of EPC 1 . ^^^ Although RFP is highly expressed as 58 and 68 kDa proteins in mouse testis , the EPC 1 CT region more strongly interacted with the 68 kDa form than the EPcA or EPcB region . ^^^ |