Arabidopsis AT-hook protein TEK positively regulates the expression of arabinogalactan proteins in controlling nexine layer formation in the pollen wall.
Arabidopsis AT-hook protein TEK positively regulates the expression of arabinogalactan proteins in controlling nexine layer formation in the pollen wall.
复制标题
DOI：
10.1093/mp/ssu114
复制
发表时间：
2014-10
期刊：
影响因子：
27.5
通讯作者：
Q. Jia;Jun Zhu;Xiaofeng Xu;Y. Lou;Zhan-Lin Zhang;Zhiping Zhang;Zhongnan Yang
中科院分区：
文献类型：
--
作者：
Q. Jia;Jun Zhu;Xiaofeng Xu;Y. Lou;Zhan-Lin Zhang;Zhiping Zhang;Zhongnan Yang
内质层是花粉壁的保守层。我们之前报道过，通过AT-HOOK (TEK)，转座因子沉默的敲除突变体中缺乏内链蛋白层。在这项工作中，我们表征了TEK在花粉发育中的分子功能，并确定了TEK的直接靶点，阿拉伯半乳聚糖蛋白（AGPs），它负责内酯的形成。电泳迁移率转移试验（EMSA）表明，TEK可以直接结合核基质附着区（MAR）。tek与tek - srdx转基因系表型相似，表明tek在花药发育过程中发挥转录激活作用。芯片分析共鉴定出TEK下游661个基因，包括4个编码AGPs、AGP6、AGP11、AGP23和AGP40的基因。使用flag标记的TEK补体系进行染色质免疫沉淀（ChIP）和PCR分析表明，TEK富含这四个基因的启动子。EMSA进一步证实TEK与AGP6启动子结合。由TEK启动子驱动的AGP6在TEK中的表达可以部分挽救内质素的形成和植物的育性。这些结果表明，TEK直接调节了花药中AGPs的表达。有人提出糖蛋白是花粉壁内质层的重要组成部分。
Nexine is a conserved layer of the pollen wall. We previously reported that the nexine layer is absent in the knockout mutant of TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK). In this work, we characterized the molecular function of TEK in pollen development and identified direct targets of TEK, Arabinogalactan proteins (AGPs), which are responsible for nexine formation. Electrophoretic mobility shift assay (EMSA) showed that TEK can directly bind to the nuclear matrix attachment region (MAR). Phenotypic similarity between tek and the TEK-SRDX transgenic lines indicated that TEK plays a role in transcriptional activation in anther development. Microarray analysis identified a total of 661 genes downstream of TEK, including four genes encoding AGPs, AGP6, AGP11, AGP23 and AGP40. Chromatin immunoprecipitation (ChIP) followed by PCR analysis using the FLAG-tagged TEK complement lines suggested that TEK is enriched in the promoters of these four genes. EMSA further confirmed that TEK binds to the AGP6 promoter. The expression of AGP6 driven by the TEK promoter in tek can partially rescue both nexine formation and plant fertility. These results show that TEK directly regulates AGPs expression in the anther. It is proposed that glycoproteins are an essential component of the nexine layer in the pollen wall.