WTAP Full-Length MS Protein Standard (NP_004897), Labeled with [U- 13C6, 15N4]-L-Arginine and [U- 13C6, 15N2]-L-Lysine, was produced in human 293 cells (HEK293) with fully chemically defined cell culture medium to obtain incorporation efficiency at Creative-Proteomics. The Wilms tumor suppressor gene WT1 appears to play a role in both transcriptional and posttranscriptional regulation of certain cellular genes. This gene encodes a WT1-associating protein, which is a ubiquitously expressed nuclear protein. Like WT1 protein, this protein is localized throughout the nucleoplasm as well as in speckles and partially colocalizes with splicing factors. Alternative splicing of this gene results in several transcript variants encoding three different isoforms.