Extended Data Fig. 9. A working model for the role of the coiled coil protein FLL2 to promote nuclear bodies important for polyadenylation at specific sites.
At efficient polyA sites, the cleavage and polyadenylation specificity factor (CPSF) complex specifically recognizes the cis-acting motif upstream of the cleavage site, catalyzes pre-mRNA cleavage, and recruits polyA polymerase to initiate polyadenylation. At other sites, phase-separated FCA droplets compartmentalize 3’ end processing factors to enhance polyadenylation.