Description of the CFI polyadenylation factor of the Arabidopsis thaliana model plant

Cleavage factor I (CFI) is a four-subunit protein complex of the pre-mRNA 3' end processing machinery in eukaryotes. In Arabidopsis, AtCFI25a, AtCFI25b, AtCFI59, and AtCFI68 has been identified as components of AtCFI. Plants with loss-of-function for AtCFI25a or AtCFI59 and AtCFI68, showed less diverse usages of 3' UTR cleavage and polyadenylation sites, favoring shorter, and sometimes longer, 3' UTRs. Furthermore, transcripts coding for AtCFI subunits showed altered 3' UTR cleavage site selections in these mutants, suggesting self-regulation function of AtCFI. Genome-wide analyses revealed that genes involved in light intensity, light harvesting, photosynthesis and cold responses showed significant dependence on AtCFI function. Taken together, here we report novel molecular function of CFI in 3' UTR end regulation, using null alleles of CFI subunits.