Interaction of maize Opaque-2 and the transcriptional co-activators GCN5 and ADA2, in the modulation of transcriptional activity
Interaction of maize Opaque-2 and the transcriptional co-activators GCN5 and ADA2, in the modulation of transcriptional activity
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DOI：
10.1007/s11103-004-0553-z
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发表时间：
2004-05-01
影响因子：
5.1
通讯作者：
Thompson, RD
中科院分区：
文献类型：
--
作者：
Bhat, RA;Borst, JW;Thompson, RD
玉米不透明-2 （ZmO2）是一种bZip类转录因子，可以激活一系列在胚乳发育成熟阶段表达的基因的转录。激活需要一个或多个增强子结合位点的存在，这赋予了ZmO2在异源启动子和异源植物细胞类型（如烟草叶肉原生质体）上激活的倾向。ZmO2转录激活所需的区域被定位在ZmO2序列n端部分的一段酸性残基上，该区域在o2相关的bZip因子序列之间是保守的。之前我们发现了酵母转录共激活因子GCN5和ADA2的玉米同源物，它们与核小体修饰和转录有关。在目前的研究中，我们已经证明ZmO2的转录调节涉及ZmO2与ZmADA2和ZmGCN5的核内相互作用。福斯特共振能量转移（FRET）为基础的技术使我们能够估计这些分子间相互作用的细胞内位置。作为这些核内相互作用的功能读数，我们使用ZmO2响应玉米b-32启动子在ZmGCN5和ZmADA2存在和不存在的情况下驱动β -葡糖醛酸酶（GUS）。我们的研究结果表明，ZmADA2和ZmGCN5的募集可能调节了ZmO2对b-32启动子的转激活，ZmGCN5和ZmO2之间可能存在与ZmADA2氨基末端结合的竞争。这些结果可以作为植物中涉及酸性激活域的其他转录调节过程的范例。
Maize Opaque-2 (ZmO2), a bZip class transcription factor has been shown to activate the transcription of a series of genes expressed in the maturation phase of endosperm development. Activation requires the presence of one or more enhancer binding sites, which confer the propensity for activation by ZmO2 on heterologous promoters and in heterologous plant cell types, such as tobacco mesophyll protoplasts. The region of ZmO2 required for conferring transcriptional activation has been localised to a stretch of acidic residues in the N-terminal portion of the ZmO2 sequence, which is conserved between O2-related bZip factor sequences. Previously we identified the maize homologues of yeast transcriptional co-activators GCN5 and ADA2 that are implicated in nucleosome modification and transcription. In the present study we have shown that transcriptional modulation by ZmO2 involves the intranuclear interaction of ZmO2 with ZmADA2 and ZmGCN5. Forster resonance energy transfer (FRET) based techniques have enabled us to estimate the intracellular site of these intermolecular interactions. As a functional readout of these intranuclear interactions, we used the ZmO2 responsive maize b-32 promoter to drive the beta-glucuronidase (GUS) in the presence and absence of ZmGCN5 and ZmADA2. Our results suggest that the likely recruitment of ZmADA2 and ZmGCN5 modulates the transactivation of b-32 promoter by ZmO2 and that there may be a competition between ZmGCN5 and ZmO2 for binding to the amino-terminal of ZmADA2. The results may be taken as a paradigm for other processes of transcriptional modulation in planta involving acidic activation domains.