Cleavage And Polyadenylation Specific Factor 1 (CPSF1)

Cleavage and polyadenylation specificity factor (CPSF) is a multisubunit complex that plays a central role in 3-prime processing of pre-mRNAs. CPSF recognizes the AAUAAA signal in the pre-mRNA and interacts with other proteins to facilitate both RNA cleavage and poly(A) synthesis. CPSF1 is the largest subunit of the CPSF complex.The 1,442-amino acid protein contains a bipartite nuclear localization signal and an RNA-binding domain. Northern blot analysis revealed expression of a 5.0-kb transcript. Immunofluorescence microscopy and Western blot analysis showed expression of an exclusively nuclear 160-kD protein.