Anti-RBM21 antibodies are used in antigen-specific immunodetection in biological samples. The target RBM21 is a known alias name of the protein terminal uridylyl transferase 1, U6 snRNA-specific, encoded by the TUT1 gene in humans. This 874-amino acid residue protein is reported to be a Poly(A) polymerase that creates the 3'-poly(A) tail of specific pre-mRNAs. It is localized to the nucleus of the cell and features phosphorylated post-translational modifications. In terms of tissue expression, it is widely expressed across many tissue types.