Component of the cleavage factor Im (CFIm) complex that functions as an activator of the pre-mRNA 3′-end cleavage and polyadenylation processing required for the maturation of pre-mRNA into functional mRNAs (PubMed:17024186, PubMed:29276085, PubMed:8626397). CFIm contributes to the recruitment of multiprotein complexes on specific sequences on the pre-mRNA 3′-end, so called cleavage and polyadenylation signals (pA signals) (PubMed:17024186, PubMed:8626397). Most pre-mRNAs contain multiple pA signals, resulting in alternative cleavage and polyadenylation (APA) producing mRNAs with variable 3′-end formation (PubMed:23187700, PubMed:29276085). The CFIm complex acts as a key regulator of cleavage and polyadenylation site choice during APA through its binding to 5′-UGUA-3′ elements localized in the 3′-untranslated region (UTR) for a huge number of pre-mRNAs (PubMed:20695905, PubMed:29276085). CPSF7 activates directly the mRNA 3′-processing machinery (PubMed:29276085). Binds to pA signals in RNA substrates (PubMed:17024186, PubMed:8626397).
