A possible working mechanism for rice SVP-group MADS-box proteins as negative regulators of brassinosteroid responses
A possible working mechanism for rice SVP-group MADS-box proteins as negative regulators of brassinosteroid responses
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DOI：
10.4161/psb.3.7.5677
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发表时间：
2008-01-01
影响因子：
2.9
通讯作者：
An, Gynheung
中科院分区：
文献类型：
--
作者：
Lee, Shinyoung;Jeong, Dong-Hoon;An, Gynheung
大多数SVP组MADS盒基因控制分生组织的身份和开花时间。在水稻中，它们在调节前者中的作用是保守的;然而，它们在决定后者中的参与并不显著。典型地，水稻SVP组MADS盒蛋白在油菜素类固醇（BR）反应中起负调节作用。为了阐明分子机制，我们研究了这些蛋白质的定位模式，并发现，出乎意料的是，它们在细胞核中不是特异性的，无论是单独表达还是同时表达。然而，有趣的是，OsMADS 22和OsMADS 47与OsMADS 50一起沿着移位到核中，而OsMADS 55抑制OsMADS 50的核定位。OsBLE启动子区的CArG基序和ARF结合位点之间存在一个重叠的顺式元件，BR处理和SVP RNAi植物均上调该元件。这些观察结果表明，BR介导的信号可以诱导靶基因的表达，通过删除的SVP组MADS盒蛋白，预先占据BR下游基因的启动子。
Most SVP-group MADS-box genes control meristem identity and flowering time. In rice, their roles in regulating the former are well-conserved; however, their involvement in determining the latter is not significant. Characteristically, rice SVP-group MADS-box proteins work as negative regulators in brassinosteroid (BR) responses. To elucidate the molecular mechanism, we studied the localization patterns for these proteins and found that, unexpectedly, they were not specific in the nucleus, whether expressed alone or simultaneously. Interestingly however, OsMADS22 and OsMADS47 were translocated into the nucleus along with OsMADS50 while OsMADS55 inhibited the nuclear localization of OsMADS50. An overlapping cis-element exists between the CArG motif and ARF binding site on the promoter region of OsBLE, which is upregulated by BR treatment and in SVP RNAi plants. These observations suggest that BR-mediated signals may induce target gene expression by removing the SVP-group MADS-box proteins that preoccupy the promoters of BR downstream genes.