Plant NAC-type transcription factor proteins contain a NARD domain for repression of transcriptional activation
Plant NAC-type transcription factor proteins contain a NARD domain for repression of transcriptional activation
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DOI：
10.1007/s00425-010-1238-2
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发表时间：
2010-10-01
期刊：
影响因子：
4.3
通讯作者：
Chen, Shou-Yi
中科院分区：
文献类型：
--
作者：
Hao, Yu-Jun;Song, Qing-Xin;Chen, Shou-Yi
植物特异性转录因子NAC蛋白在许多生物学过程中发挥重要作用，如发育、衰老、形态建成和胁迫信号转导途径。在NAC家族中，一些成员作为转录激活因子，而另一些则作为抑制因子。在本研究中，我们发现大豆GmNAC 20的全长不具有转录激活活性，但其羧基端激活结构域在酵母系统中具有较高的转录激活活性。缺失实验表明，在NAC DNA结合结构域的d亚结构域中存在一个35个氨基酸的活性阻遏结构域，命名为NARD（NAC阻遏结构域）。当NARD与转录因子的氨基端或羧基端融合时，可以降低多种转录因子的转录激活能力。NARD样序列也存在于其他NAC家族成员中，当与植物原生质体检测系统中的VP16融合时，它们是功能性阻遏结构域。保守氨基酸残基的突变分析表明，疏水性LVFY基序可能部分有助于抑制功能。据推测，抑制结构域NARD和羧基末端激活结构域之间的相互作用可能最终决定NAC家族蛋白调节下游基因表达的能力。
Plant-specific transcription factor NAC proteins play essential roles in many biological processes such as development, senescence, morphogenesis, and stress signal transduction pathways. In the NAC family, some members function as transcription activators while others act as repressors. In the present study we found that though the full-length GmNAC20 from soybean did not have transcriptional activation activity, the carboxy-terminal activation domain of GmNAC20 had high transcriptional activation activity in the yeast assay system. Deletion experiments revealed an active repression domain with 35 amino acids, named NARD (NAC Repression Domain), in the d subdomain of NAC DNA-binding domain. NARD can reduce the transcriptional activation ability of diverse transcription factors when fused to either the amino-terminal or the carboxy-terminal of the transcription factors. NARD-like sequences are also present in other NAC family members and they are functional repression domain when fused to VP16 in plant protoplast assay system. Mutation analysis of conserved amino acid residues in NARD showed that the hydrophobic LVFY motif may partially contribute to the repression function. It is hypothesized that the interactions between the repression domain NARD and the carboxy-terminal activation domain may finally determine the ability of NAC family proteins to regulate downstream gene expressions.