A review of target gene specificity of flavonoid R2R3-MYB transcription factors and a discussion of factors contributing to the target gene selectivity
A review of target gene specificity of flavonoid R2R3-MYB transcription factors and a discussion of factors contributing to the target gene selectivity
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DOI：
10.1007/s11515-013-1281-z
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发表时间：
2013-09
期刊：
影响因子：
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通讯作者：
Y. Lai;Huanxiu Li;M. Yamagishi
中科院分区：
文献类型：
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作者：
Y. Lai;Huanxiu Li;M. Yamagishi
在花或果实发育过程中，类黄酮生物合成基因经常以时间的方式进行协调调节，导致类黄酮化合物的特定积累谱。R2R3-MYB类转录因子“招募”一组生物合成基因来产生类黄酮，因此，R2R3-MYB负责结构基因的协调表达。虽然到目前为止，关于参与类黄酮积累的R2R3-MYB的识别和功能特征的丰富信息是可用的，但这是第一次对类黄酮途径中MYB因子的全球调控进行综述。研究表明，花青素、黄酮黄酮醇/3-脱氧黄酮类(FFD)、原花青素(PA)和异黄酮类化合物受R2R3-MYB不同亚类的独立调控。此外，FFD特异的R2R3-MYB偏爱早期生物合成基因(EBGs)作为其靶基因；来自双子叶植物的花青素特异的R2R3-MYB本质上调节晚期生物合成基因(LBGS)；其余的R2R3-MYB具有更广泛的靶基因特异性。为了阐明R2R3-MYB之间差异靶基因特异性的本质，我们分析了R2R3-MYB的DNA结合域(也称为MYB-域)和识别顺式元件的分布。我们鉴定了位于双子叶花青素R2R3-MYB螺旋-3或之前的四个保守氨基酸残基，这可能解释了不同的DNA序列识别以及随后对其余R2R3-MYB TF的不同靶基因特异性。
Flavonoid biosynthetic genes are often coordinately regulated in a temporal manner during flower or fruit development, resulting in specific accumulation profiles of flavonoid compounds. R2R3-MYB-type transcription factors (TFs) “recruit” a set of biosynthetic genes to produce flavonoids, and, therefore, R2R3-MYBs are responsible for the coordinated expression of structural genes. Although a wealth of information regarding the identified and functionally characterized R2R3-MYBs that are involved in flavonoid accumulation is available to date, this is the first review on the global regulation of MYB factors in the flavonoid pathway. The data presented in this review demonstrate that anthocyanin, flavone/flavonol/3-deoxyflavonoid (FFD), proanthocyanidin (PA), and isoflavonoid are independently regulated by different subgroups of R2R3-MYBs. Furthermore, FFD-specific R2R3-MYBs have a preference for early biosynthetic genes (EBGs) as their target genes; anthocyanin-specific R2R3-MYBs from dicot species essentially regulate late biosynthetic genes (LBGs); the remaining R2R3-MYBs have a wider range of target gene specificity. To elucidate the nature of the differential target gene specificity between R2R3-MYBs, we analyzed the DNA binding domain (also termed the MYB-domain) of R2R3-MYBs and the distribution of the recognition cis-elements. We identified four conserved amino acid residues located in or just before helix-3 of dicot anthocyanin R2R3-MYBs that might account for the different recognition DNA sequence and subsequently the different target gene specificity to the remaining R2R3-MYB TFs.