Immunogen sequence: REKPKSRKEL IEELIAKSKQ EKRERQAQRE DALELTEKLD QDWKEIQTLL SHKTPKSENR DKKEKPKPDA YDMMVRELGF EMKAQPSNRM KT Highest antigen sequence identity to the following orthologs: Mouse - 86%, Rat - 89%. Involved in nucleolar processing of pre-18S ri