Cleavage Stimulation Factor 1 (CSTF1)

CSTF1 encodes one of three subunits which combine to form cleavage stimulation factor (CSTF). CSTF is involved in the polyadenylation and 3'end 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.

The BARD1-CSTF1 interaction inhibited polyadenylation in vitro. BARD1, like CSTF1, interacts with RNA polymerase-2. BARD1, BRCA1, and CSTF1 were shown to associate in vivo.BARD1 inhibits pre-mRNA 3-prime cleavage in vitro and that the same region of BARD1 required for binding of CSTF1 is necessary for inhibiting 3-prime pre-mRNA cleavage.