CSTF1 Full-Length MS Protein Standard (NP_001315), 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. This gene encodes one of three subunits which combine to form cleavage stimulation factor (CSTF). CSTF is involved in the polyadenylation and 3end cleavage of pre-mRNAs. Similar to mammalian G protein beta subunits, this protein contains transducin-like repeats. Several transcript variants with different 5 UTR, but encoding the same protein, have been found for this gene.