VASCULAR-RELATED NAC-DOMAIN 7 directly regulates the expression of a broad range of genes for xylem vessel formation
VASCULAR-RELATED NAC-DOMAIN 7 directly regulates the expression of a broad range of genes for xylem vessel formation
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DOI：
10.1111/j.1365-313x.2011.04514.x
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发表时间：
2011-05-01
期刊：
影响因子：
7.2
通讯作者：
Demura, Taku
中科院分区：
文献类型：
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作者：
Yamaguchi, Masatoshi;Mitsuda, Nobutaka;Demura, Taku
拟南芥NAC结构域转录因子VASCULAR-RELATED NAC-DOMAIN 7（VND 7）是木质部导管分化的关键调控因子。为了鉴定VND 7的直接靶基因，我们使用拟南芥转基因株系进行了全局转录组分析，其中VND 7活性可以在诱导后诱导。该分析鉴定了63个推定的VND 7的直接靶基因，其编码广泛的蛋白质，如转录因子、不规则木质部蛋白和蛋白水解酶，已知与木质部导管形成密切相关。重组VND 7蛋白结合候选直接靶基因中存在的几个启动子序列：具体地，在木质部半胱氨酸肽酶1的启动子中，两个不同的区域被证明负责VND 7结合。我们还发现VND 7的表达恢复了nst 1 nst 3双突变体花序茎纤维细胞中次生细胞壁的形成，以及NAC次生壁增厚促进因子3（NST 3）的表达，然而，仅观察到VND 7表达导致的血管型次生壁沉积。这些结果表明，VND 7上调，直接和/或间接，许多基因参与了广泛的过程中木质部导管分化，其靶基因是部分不同的NST。
The Arabidopsis thaliana NAC domain transcription factor, VASCULAR-RELATED NAC-DOMAIN7 (VND7), acts as a key regulator of xylem vessel differentiation. In order to identify direct target genes of VND7, we performed global transcriptome analysis using Arabidopsis transgenic lines in which VND7 activity could be induced post-translationally. This analysis identified 63 putative direct target genes of VND7, which encode a broad range of proteins, such as transcription factors, IRREGULAR XYLEM proteins and proteolytic enzymes, known to be closely associated with xylem vessel formation. Recombinant VND7 protein binds to several promoter sequences present in candidate direct target genes: specifically, in the promoter of XYLEM CYSTEINE PEPTIDASE1, two distinct regions were demonstrated to be responsible for VND7 binding. We also found that expression of VND7 restores secondary cell wall formation in the fiber cells of inflorescence stems of nst1 nst3 double mutants, as well as expression of NAC SECONDARY WALL THICKENING PROMOTING FACTOR3 (NST3, however, the vessel-type secondary wall deposition was observed only as a result of VND7 expression. These findings indicated that VND7 upregulates, directly and/or indirectly, many genes involved in a wide range of processes in xylem vessel differentiation, and that its target genes are partially different from those of NSTs.