Plays a role in the regulation of flowering time in the autonomous flowering pathway by decreasing FLOWERING LOCUS C mRNA levels. Required for the negative autoregulation of FCA expression. Acts probably as an RNA 3' end-processing factor. Required for growth and development in plants. Interacts transiently (via the PPLPP motifs) with FCA (via the WW domain). Interacts with CPSF73-I, CPSF73-II, CPSF100 and CPSF160 in the CPSF complex. The FCA/FY interaction leads to changes in FY/CPSF complex composition. A number of isoforms are produced. According to EST sequences. Expressed in embryos, in shoot and root meristems and in the vasculature. At globular stage, expressed throughout the embryo, endosperm and surrounding maternal seed tissue. From the heart-stage, expression restricted to the embryo and the funiculus. Embryo lethal.