WTAP,also named as KIAA0105 and hFL(2)D,is previously identified as a protein associated with Wilms' tumor-1 (WT-1) protein that is essential for the development of the genitourinary system. It is a Pre-mRNA-splicing regulator protein. It is a regulatory subunit of the WMM N6-methyltransferase complex which plays a role in the efficiency of mRNA splicing and processing and mRNA stability. It is required for accumulation of METTL3 and METTL14 to nuclear speckle.