Henderson Ian R, Liu Fuquan, Drea Sinead, Simpson Gordon G, Dean Caroline
Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, UK.
Development. 2005 Aug;132(16):3597-607. doi: 10.1242/dev.01924. Epub 2005 Jul 20.
The autonomous pathway functions to promote flowering in Arabidopsis by limiting the accumulation of the floral repressor FLOWERING LOCUS C (FLC). Within this pathway FCA is a plant-specific, nuclear RNA-binding protein, which interacts with FY, a highly conserved eukaryotic polyadenylation factor. FCA and FY function to control polyadenylation site choice during processing of the FCA transcript. Null mutations in the yeast FY homologue Pfs2p are lethal. This raises the question as to whether these essential RNA processing functions are conserved in plants. Characterisation of an allelic series of fy mutations reveals that null alleles are embryo lethal. Furthermore, silencing of FY, but not FCA, is deleterious to growth in Nicotiana. The late-flowering fy alleles are hypomorphic and indicate a requirement for both intact FY WD repeats and the C-terminal domain in repression of FLC. The FY C-terminal domain binds FCA and in vitro assays demonstrate a requirement for both C-terminal FY-PPLPP repeats during this interaction. The expression domain of FY supports its roles in essential and flowering-time functions. Hence, FY may mediate both regulated and constitutive RNA 3'-end processing.
自主途径通过限制开花抑制因子开花位点C（FLC）的积累来促进拟南芥开花。在该途径中，FCA是一种植物特异性的核RNA结合蛋白，它与FY相互作用，FY是一种高度保守的真核多聚腺苷酸化因子。FCA和FY在FCA转录本加工过程中控制多聚腺苷酸化位点的选择。酵母FY同源物Pfs2p中的无效突变是致死的。这就提出了一个问题，即这些基本的RNA加工功能在植物中是否保守。对一系列fy突变等位基因的表征表明，无效等位基因是胚胎致死的。此外，沉默FY而不是FCA对烟草的生长有害。晚花fy等位基因是亚效等位基因，表明在FLC的抑制中完整的FY WD重复序列和C末端结构域都需要。FY C末端结构域结合FCA，体外实验表明在这种相互作用过程中C末端FY-PPLPP重复序列都需要。FY的表达结构域支持其在基本功能和开花时间功能中的作用。因此，FY可能介导受调控的和组成型的RNA 3'末端加工。
