Characterization of wound-responsive RNA-binding proteins and their splice variants in Arabidopsis
Characterization of wound-responsive RNA-binding proteins and their splice variants in Arabidopsis
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DOI：
10.1007/s11103-008-9302-z
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发表时间：
2008-05-01
影响因子：
5.1
通讯作者：
Assmann, Sarah M.
中科院分区：
文献类型：
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作者：
Bove, Jerome;Kim, Cha Young;Assmann, Sarah M.
我们报道了三个UBA2基因(UBA2a、-b和-c；对应于At3g56860、At2g41060和At3g15010)的特征，它们编码与蚕豆AKIP1和其他异源核核糖核蛋白(HnRNP)类型的RNA结合蛋白高度同源的拟南芥蛋白。体外RNA结合实验表明，这三种UBA2蛋白均能与均聚体有效结合。UBA2-GFP的瞬时表达证明这三种UBA2蛋白定位于细胞核。RNA凝胶印迹、RT-PCR和启动子：：GUS分析表明，UBA2转录产物在所有器官中都有表达。UBA2基因的选择性剪接只影响3‘-非翻译区(UTRs)：检测到UBA2a有六种不同的剪接变体，UBA2b和UBA2c各有两种。RT-PCR和实时荧光定量RT-PCR分析表明，UBA2的转录水平受损伤的调控，剪接变异体UBA2a.1和UBA2c.1在机械损伤后增加。损伤对基因表达的影响是通过依赖茉莉酸甲酯(MeJA)和依赖低聚半乳糖醛酸苷(OGA)的途径转导的。然而，无论是MeJA还是OGA处理都没有改变任何UBA2转录本的水平，而与伤害反应有关的其他植物激素，乙烯和脱落酸(ABA)也对UBA2转录本的积累没有影响。综上所述，这些结果暗示这三个UBA2基因编码hnRNP类型的核RNA结合蛋白，这些蛋白在一种新的创伤信号转导途径中发挥功能。
We report the characterization of three UBA2 genes (UBA2a, -b, and -c; corresponding to At3g56860, At2g41060, and At3g15010) encoding Arabidopsis thaliana proteins with high homology to Vicia faba AKIP1 and other heterogeneous nuclear ribonucleoprotein (hnRNP)-type RNA-binding proteins. In vitro RNA binding assays revealed that the three UBA2 proteins interact efficiently with homoribopolymers. Biolistic transient expression of UBA2-GFPs demonstrated that the three UBA2 proteins localize to the nucleus. Expression analysis by RNA gel blot, RT-PCR, and promoter::GUS assays showed that UBA2 transcripts are present in all organs. UBA2 genes are subject to alternative splicing affecting only the 3'-untranslated regions (UTRs): six different splice variants were detected for UBA2a, and two each were found for UBA2b and UBA2c. RT-PCR and quantitative real-time RT-PCR analysis showed that the levels of UBA2 transcripts are regulated by wounding in a splice variant-specific manner: splice variants UBA2a.1 and UBA2c.1 increased following mechanical wounding. Wounding effects on gene expression are transduced by methyl jasmonate (MeJA)-dependent and oligogalacturonide (OGA)-dependent pathways. However, neither MeJA nor OGA treatment altered levels of any of the UBA2 transcripts, and other plant hormones implicated in wound responses, ethylene and abscisic acid (ABA), also had no effect on accumulation of UBA2 transcripts. Taken together, these results imply that the three UBA2 genes encode hnRNP-type nuclear RNA-binding proteins that function in a novel wound signal transduction pathway.