Indirect ABA-dependent regulation of seed storage protein genes by FUSCA3 transcription factor in Arabidopsis
Indirect ABA-dependent regulation of seed storage protein genes by FUSCA3 transcription factor in Arabidopsis
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DOI：
10.1093/pcp/pci031
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发表时间：
2005-02-01
影响因子：
4.9
通讯作者：
Hattori, T
中科院分区：
文献类型：
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作者：
Kagaya, Y;Okuda, R;Hattori, T
控制种子成熟的关键转录因子脱落酸不敏感3（ABI3）和FUSCA3（FUS3）共享同源DNA结合结构域。利用转基因植物研究了ABI 3和FUS 3对种子贮藏蛋白基因At2S3和CRC的调控。与ABI3一样，FUS3的存在导致At2S3和CRC在营养组织中的表达。FUS3介导的CRC诱导完全依赖于外源脱落酸（ABA），而At2S3在没有ABA的情况下被弱诱导，但在ABA的情况下被强烈增强。FUS3诱导的CRC和At2S3表达的这种ABA依赖性与ABI3观察到的相似。然而，动力学分析揭示了FUS3或ABI 3的ABA依赖性CRC调控机制之间的差异，以及靶基因之间的差异。虽然FUS3对At2S3的激活是快速的，但在ABA存在下FUS3对CRC的诱导，以及在FUS3存在下ABA对CRC的诱导，需要显著更长的时间（24 - 36小时）。这表明涉及一种间接机制，需要ABA和FUS3依赖性合成中间调节因子。由FUS3 B3结构域和异源激活结构域和核定位信号组成的嵌合蛋白表现出与野生型FUS3所观察到的ABA调节的紧密耦合。FUS3和ABI3的同时诱导没有导致CRC和A0S3的协同活化。在此基础上，讨论了FUS3和ABI3对种子贮藏蛋白基因调控机制的异同。
The key transcription factors that control seed maturation, ABSCISIC ACID INSENSITIVE3 (ABI3) and FUSCA3 (FUS3), share homologous DNA-binding domains. Regulation of seed storage protein genes At2S3 and CRC by ABI3 and FUS3 was investigated using transgenic plants in which ABI3 and FUS3 could be ectopically induced by steroid hormones. Like ABI3, the presence of FUS3 led to expression of At2S3 and CRC in vegetative tissues. FUS3-mediated induction of CRC was completely dependent on exogenous abscisic acid (ABA), while At2S3 was weakly induced without ABA but strongly enhanced with ABA. This ABA dependency of FUS3-induced CRC and At2S3 expression was similar to that observed for ABI3. However, kinetic analysis revealed distinctions between the mechanisms of ABA-dependent CRC regulation by FUS3 or ABI3, and between target genes. While At2S3 activation by FUS3 was rapid, CRC induction by FUS3 in the presence of ABA, and by ABA followed by the presence of FUS3, took a significantly longer time (24-36 h). This suggested the involvement of an indirect mechanism requiring the ABA-and FUS3-dependent synthesis of intermediate regulatory factor(s). A chimeric protein composed of the FUS3 B3 domain, and a heterologous activation domain and nuclear localization signal exhibited a tight coupling with ABA regulation as observed for wild-type FUS3. Simultaneous induction of FUS3 and ABI3 did not result in the synergistic activation of CRC and AOS3. Based on these results, similarities and differences in the mechanisms of seed storage protein gene regulation by FUS3 and ABI3 are discussed.