Functional Spliceosome Associated Protein 94 (fSAP94)

The deduced 843-amino acid protein has a calculated molecular mass of 120 kD. It contains an N-terminal proline-rich domain, followed by an RNA recognition motif, a region rich in RE/RD dipeptides, and a C-terminal PWI domain predicted to be involved in RNA binding and 3-prime end processing.

Immunohistochemical analysis revealed that RED120 was concentrated in interchromatin granules, or nuclear speckles, and additional staining was detected in the cytoplasm.RED120 associated with multiple splicing components, including CBP80 (NCBP1), Sm proteins , and small nuclear RNAs. RNase treatment abolished the interaction between RED120 and CBP80, but not the interactions between RED120 and other splicing components.