Poster abstracts
Poster number 34 submitted by Diego Vallejos
The Role of the FY C-Terminal Domain in Flowering Regulation in Arabidopsis thaliana
Diego R. Vallejos Burgoa (Department of Plant and Soil Sciences, University of Kentucky), Lichun Zhou (Department of Plant and Soil Sciences, University of Kentucky), Arthur G. Hunt (Department of Plant and Soil Sciences, University of Kentucky)
Abstract:
FY is a 3-end processing factor that is the plant ortholog of WDR33. In addition to being a core
polyadenylation factor, FY is involved in the regulation of flowering time. FY regulates flowering by controlling the expression of the major floral repressor FLOWERING LOCUS C (FLC); FY works in concert with an RNA binding protein (FCA) to negatively regulate FLC expression, thereby promoting flowering. The role(s) of FY in the regulation of flowering are mediated by a novel C-terminal domain of the protein. This C terminal region of FY contains two PPLP motifs that interact with a WW domain in FCA. We hypothesize that over-expression of the C-terminal region of FY (FY-C) could interfere with normal FCA regulation and consequently alter FLC expression and flowering time. To test this hypothesis, a construct encoding the FY-C domain was expressed the Col-0 background. The expression of the transgene in transgenic lines was confirmed by immunoblot analysis. Flowering times of the transgenic plants were measured and the expression levels of FLC and FCA were examined by qRT-PCR. Our results showed that flowering time was significantly delayed in plants that over-express the C-terminal domain of FY, thus supporting our hypothesis. In addition, FLC expression was
increased in FY-C transgenic plants, consistent with the flowering phenotype. These results support a role for the C-terminal region of FY in the regulation of the FCAFLC flowering pathway and show that expression of FY-C affects normal regulation of flowering time. We propose that the FY-C domain acts by sequestering proteins that interact with FY, thereby preventing FY from inhibiting expression of FLC. As a next step, we will perform proteomic analysis of FY-C transgenic plants to identify proteins or protein complexes that interact with FY-C and may contribute to the observed phenotype.
References:
1.Simpson, G.G., et al., FY is an RNA 3' end-processing factor that interacts with FCA to control the Arabidopsis floral transition. Cell, 2003. 113(6): p. 77787.
2.Henderson, I.R., et al., An allelic series reveals essential roles for FY in plant development in addition to flowering-time control. Development, 2005. 132(16): p. 35973607.
Keywords: alternative polyadenylation, flowering, Arabidopsis