Arabidopsis Deadenylases AtCAF1a and AtCAF1b Play Overlapping and Distinct Roles in Mediating Environmental Stress Responses
Arabidopsis Deadenylases AtCAF1a and AtCAF1b Play Overlapping and Distinct Roles in Mediating Environmental Stress Responses
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DOI：
10.1104/pp.109.149005
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发表时间：
2010-02-01
期刊：
影响因子：
7.4
通讯作者：
Dehesh, Katayoon
中科院分区：
文献类型：
--
作者：
Walley, Justin W.;Kelley, Dior R.;Dehesh, Katayoon
为了在不断变化的环境中保持稳态，生物体已经进化出重新编程基因表达的机制。调节基因表达的一个中心机制是信使RNA（mRNA）降解，其由聚（A）尾缩短（去腺苷酸化）引发。CCR 4-CAF 1复合物是催化mRNA去腺苷化的主要酶复合物，在真核生物中是保守的。然而，这一全球性的监管复杂的组件和功能还没有得到很好的特点，在植物。在这里，我们调查的CAF 1家族在拟南芥（拟南芥）。我们确定了11个AtCAF 1同源物，并表明这些基因的一个子集是响应机械创伤，其中AtCAF 1a和AtCAF 1b的表达水平是迅速和短暂的创伤诱导。各种AtCAF 1的差异表达谱表明，并不是所有的AtCAF 1基因都参与转录水平的应激反应调节。通过Atcaf 1a和Atcaf 1b突变体在受伤前后不同时间点的转录谱鉴定的错误表达基因的比较表明，AtCAF 1a和AtCAF 1b靶向具有时间特异性的去腺苷化的共享和独特的转录本。与AtPI 4K γ 3转录物表现出Atcaf 1b丰度的最大增加一致，AtCAF 1b靶向AtPI 4K γ 3 mRNA进行去腺苷化。胁迫耐受性试验表明AtCAF 1a和AtCAF 1b参与介导非生物胁迫反应。然而，AtCAF 1a和AtCAF 1b并不是在所有情况下都是功能冗余的，也不是对所有环境应力都是必不可少的。这些发现表明，这些密切相关的蛋白质表现出重叠和不同的作用，mRNA去腺苷化和调解的压力反应。
To maintain homeostasis in an ever-changing environment organisms have evolved mechanisms to reprogram gene expression. One central mechanism regulating gene expression is messenger RNA (mRNA) degradation, which is initiated by poly(A) tail shortening (deadenylation). The carbon catabolite repressor 4-CCR4 associated factor1 (CCR4-CAF1) complex is the major enzyme complex that catalyzes mRNA deadenylation and is conserved among eukaryotes. However, the components and functions of this global regulatory complex have not been well characterized in plants. Here we investigate the CAF1 family in Arabidopsis (Arabidopsis thaliana). We identify 11 AtCAF1 homologs and show that a subset of these genes are responsive to mechanical wounding, among them are AtCAF1a and AtCAF1b whose expression levels are rapidly and transiently induced by wounding. The differential expression profiles of the various AtCAF1s suggest that not all AtCAF1 genes are involved in stress-responsive regulation of transcript levels. Comparison of misexpressed genes identified via transcript profiling of Atcaf1a and Atcaf1b mutants at different time points before and after wounding suggests that AtCAF1a and AtCAF1b target shared and unique transcripts for deadenylation with temporal specificity. Consistent with the AtPI4K gamma 3 transcript exhibiting the largest increase in abundance in Atcaf1b, AtCAF1b targets AtPI4K gamma 3 mRNA for deadenylation. Stress-tolerance assays demonstrate that AtCAF1a and AtCAF1b are involved in mediating abiotic stress responses. However, AtCAF1a and AtCAF1b are not functionally redundant in all cases, nor are they essential for all environmental stresses. These findings demonstrate that these closely related proteins exhibit overlapping and distinct roles with respect to mRNA deadenylation and mediation of stress responses.