The 30th International Conference on Arabidopsis Research (ICAR 2019)

549 / 2019-03-15 10:54:52

FY defines the ending of mRNA in Arabidopsis through alternative polyadenylation

FY,poly(A) signals,alternative polyadenylation,poly(A) tag sequencing,post-transcriptional regulation

Plenary track > RNA Biology

FY is known for its function in flowering time regulation through its role in alternative polyadenylation (APA) of pre-mRNA of other flowering time pathway genes. However, what role FY plays in polyadenylation is not understood. It was recently demonstrated that mammalian Cleavage and Polyadenylation Specificity Factor (CPSF30) and a FY homolog WD40-domain repeat protein, WDR33, recognize canonical poly(A) signal (AAUAAA). To find how FY exerts this function of poly(A) signal recognition, we employed a poly(A) tag sequencing approach and found that at least 60% polyadenylation events were altered by FY single or double mutants with AtCPSF30. In FY, the WD40 domain has a stronger effect than the plant unique PPLPP domain. Mutations of FY disrupt AAUAAA or AAUAAA-like poly(A) signal recognition. Notably, A-rich signal usage is suppressed in WD40 mutation, while promoted in PPLPP mutations. However, neither WD40 nor PPLPP mutations aggravate APA caused by a null mutant of AtCPSF30. Furthermore, the WD40 mutation shows a preference of 3’UTR shortening, but the PPLPP domain mutation shows a preference for lengthening. Interestingly, the WD40 mutant exhibits shortens primary roots and confers late flowering with APA of related genes. Importantly, the functions of different APA transcripts generated by FY mutation were confirmed in ARK2 and a zinc ion binding protein gene. These results reveal a conserved and specific role of FY in mRNA polyadenylation and APA.