| Summary: | 碩士 === 國立中興大學 === 生物科技學研究所 === 93 === During development and cell differentiation, chromatin remodeling is essential for the reprogramming of the transcriptional control of gene expression in both plant and animal. This process was regulated by the antagonistic interaction between two groups of chromatin factors, the polycomb group (PcG) and the trithorax Group (trxG). In general, PcG proteins repress gene expression whereas trxG proteins counteract the effect of the PcG proteins. Two Arabidopsis trxG genes, ASHH1 and ASHR2, containing the SET domain were isolated and characterized in this study. ASHH1 and ASHR2 showed similar expression pattern and their mRNA was detected in plants at different developmental stages and was expressed in various organs such as roots, rosette leaves, inflorescenc, cauline leaves, flower bunds and siliques. The flowering time was significantly delayed in ashh1 mutants. In addition, the leaf development was also affected in mutants. This result indicated that ASHH1 is required for the vegetative development as well as the vegetative to reproductive transition. Further analysis indicated that the level of the flowering time genes such as FT and SOC1 was down-regulated in ashh1 mutants. This result revealed that ASHH1 is the activators of the photoperiod flowering pathway by maintaining the normal expression of these genes. To investigate the function of ASHH1 action, yeast two-hybrid screening using ASHH1 as a bait was carried out. Proteins that interacted with ASHH1 protein were identified. Further analysis of these proteins should lead a deeper understanding of the function for trxG genes in regulating plant development.
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