The Arabidopsis JAZ2 Promoter Contains a G-Box and Thymidine-Rich Module that are Necessary and Sufficient for Jasmonate-Dependent Activation by MYC Transcription Factors and Repression by JAZ Proteins
The Arabidopsis JAZ2 Promoter Contains a G-Box and Thymidine-Rich Module that are Necessary and Sufficient for Jasmonate-Dependent Activation by MYC Transcription Factors and Repression by JAZ Proteins
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DOI：
10.1093/pcp/pcr178
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发表时间：
2012-02-01
影响因子：
4.9
通讯作者：
Browse, John
中科院分区：
文献类型：
--
作者：
Figueroa, Pablo;Browse, John
茉莉酸（Jasmonate， JA）是植物防御和生殖发育的重要激素。到目前为止，早期的java响应启动子还没有很好地表征。为了在转录水平上确定参与早期JA反应的顺式作用DNA元件，我们分析了拟南芥编码jasmonate-ZIM domain2蛋白（JAZ2）基因的启动子。JAZ2::GUS植物的全长JAZ2启动子在营养组织和生殖组织中都很活跃，其在雄蕊花丝中的表达依赖于JA的生物合成。在胡萝卜原生质体和拟南芥幼苗中，我们在JAZ2启动子中发现了一个G-box元件，这是ja介导的启动子激活所必需的。在胡萝卜原生质体中，G-box及其侧翼序列的3个拷贝具有独立的ja依赖性活性，可被MYC2、MYC3和MYC4转录因子反激活。MYC2， MYC3或MYC4融合到EAR（乙烯反应因子相关的两亲性抑制）基元的表达，或JAZ1或JAZ6的表达都抑制了JA和myc依赖性JAZ2启动子的激活。要使JAZ2启动子完全被JA激活，G-box上的富胸腺嘧啶序列3'是必需的。由于G-box也存在于对JA无反应的基因中，我们认为这个富含胸腺嘧啶的序列与G-box一起为JA反应早期诱导的启动子提供了JA特异性。总之，这些结果表明，位于早期ja反应基因启动子区域的扩展G-box是体内基因诱导所必需的，可能通过MYC2， MYC3和MYC4转录因子的选择性结合。
Jasmonate (JA) is a critical hormone for both plant defense and reproductive development. Until now, early JA-responsive promoters have not been well characterized. To identify the cis-acting DNA element involved in the early JA response at the transcriptional level, we analyzed the promoter of the Arabidopsis gene encoding jasmonate-ZIM domain2 protein (JAZ2). The full-length JAZ2 promoter in JAZ2::GUS plants is active in vegetative and reproductive tissue, with expression in stamen filaments being dependent on JA biosynthesis. We identified a G-box element in the JAZ2 promoter that is required for JA-mediated promoter activation in carrot protoplasts and Arabidopsis seedlings. Three copies of a G-box and flanking sequences has autonomous JA-dependent activity and was transactivated by MYC2, MYC3 and MYC4 transcription factors in carrot protoplasts. Expression of MYC2, MYC3 or MYC4 fused to an EAR (ETHYLENE RESPONSE FACTOR-associated amphiphilic repression) motif, or expression of JAZ1 or JAZ6 all repressed JA- and MYC-dependent activation of the JAZ2 promoter. A thymidine-rich sequence 3' to the G-box was required for full JA activation of the JAZ2 promoter. Because the G-box is also present in genes unresponsive to JA, we propose that this thymidine-rich sequence together with the G-box provides JA specificity to promoters induced early in the JA response. Together, these results indicate that an extended G-box located in the promoter region of an early JA-responsive gene is required for gene induction in vivo, probably through selective binding of MYC2, MYC3 and MYC4 transcription factors.