E2F3-IT1 and retinoblastoma: As shown in Supplementary Fig. 1B, only one transcript variant of RBAT1 was present in Rb tumor cell lines; this variant had a total length of 582 bp (Supplementary Fig. S2A) and lacking coding potential (Supplementary Fig. 2B and 2C), thereby we named it as retinoblastoma associated transcript-1 (RBAT1).