The proteolytic function of the Arabidopsis 26S proteasome is required for specifying leaf adaxial identity
The proteolytic function of the Arabidopsis 26S proteasome is required for specifying leaf adaxial identity
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DOI：
10.1105/tpc.106.045013
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发表时间：
2006-10-01
期刊：
影响因子：
11.6
通讯作者：
Huang, Hai
中科院分区：
文献类型：
--
作者：
Huang, Weihua;Pi, Limin;Huang, Hai
极性形成是叶片形态发生的核心，在近轴-远轴极性建立中起作用的几个关键基因已被广泛鉴定和表征。我们先前报道了拟南芥ASYMMERTIC LEAVES 1（AS 1）和AS 2在促进叶片近轴命运中是重要的。我们获得了一个as 2增强子突变体，不对称叶增强子3（ae 3），它表现出多效性的植物表型，包括在一些叶的缺陷近轴身份。ae 3 as 2双突变体显示严重的离轴叶，这是伴随着叶远轴促进基因FILAMENTOUS FLOWER，YABBY 3，KANADI 1（KAN 1），和KAN 2的水平升高和近轴促进基因REVOLUTA的水平降低。我们鉴定了AE 3，其编码假定的26 S蛋白酶体亚基RPN 8a。此外，as 2与其他26 S亚基突变（包括rpt 2a、rpt 4a、rpt 5a、rpn 1a、rpn 9a、pad 1和pbe 1）的双突变体组合均显示出与ae 3 as 2相当的表型，尽管表型严重程度不同。由于这些突变基因编码的亚基位于26 S蛋白酶体的不同部分，因此26 S全酶的蛋白水解功能可能参与叶极性的形成。总之，我们的研究结果表明，翻译后调节是必不可少的适当的叶图案。
Polarity formation is central to leaf morphogenesis, and several key genes that function in adaxial- abaxial polarity establishment have been identified and characterized extensively. We previously reported that Arabidopsis thaliana ASYMMERTIC LEAVES1 ( AS1) and AS2 are important in promoting leaf adaxial fates. We obtained an as2 enhancer mutant, asymmetric leaves enhancer3 ( ae3), which demonstrated pleiotropic plant phenotypes, including a defective adaxial identity in some leaves. The ae3 as2 double mutant displayed severely abaxialized leaves, which were accompanied by elevated levels of leaf abaxial promoting genes FILAMENTOUS FLOWER, YABBY3, KANADI1 ( KAN1), and KAN2 and a reduced level of the adaxial promoting gene REVOLUTA. We identified AE3, which encodes a putative 26S proteasome subunit RPN8a. Furthermore, double mutant combinations of as2 with other 26S subunit mutations, including rpt2a, rpt4a, rpt5a, rpn1a, rpn9a, pad1, and pbe1, all displayed comparable phenotypes with those of ae3 as2, albeit with varying phenotypic severity. Since these mutated genes encode subunits that are located in different parts of the 26S proteasome, it is possible that the proteolytic function of the 26S holoenzyme is involved in leaf polarity formation. Together, our findings reveal that posttranslational regulation is essential in proper leaf patterning.