Co-expression of native and introduced genes reveals cryptic regulation of HMG CoA reductase expression in Arabidopsis.
Co-expression of native and introduced genes reveals cryptic regulation of HMG CoA reductase expression in Arabidopsis.
复制标题
天然基因和引入基因的共表达揭示了拟南芥中 HMG CoA 还原酶表达的神秘调控。
DOI：
10.1046/j.1365-313x.1995.07050771.x
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Learned,RM
中科院分区：
文献类型：
--
作者：
Re,EB;Jones,D;Learned,RM
在真核生物中，所有的类异戊二烯化合物都有一个共同的前体——甲戊二酸，它的合成是由3‐羟基‐3‐甲基戊二酰辅酶a （HMG CoA）还原酶催化的。为了更好地了解该酶在植物中协调类异戊二烯生物合成中的作用，拟南芥ahmg CoA还原酶在转基因拟南芥植物中异位表达。利用这种分子遗传学方法，对拟南芥的类异戊二烯生物合成进行了一些新的和基本的观察。首先，研究表明，过表达真拟南芥ismg辅酶a还原酶并不足以改变植物类异戊二烯途径中大量终产物的合成和积累。其次，转基因的活性转录似乎共同激活和解除了天然基因的表达，导致HMG辅酶a还原酶mRNA水平的显著升高。最后，尽管在这些转基因植物中表达了非常高水平的HMG辅酶a还原酶mRNA，但酶活性仅略有增加。综上所述，这些数据表明HMG CoA还原酶的表达在植物和动物中都受到多个水平的调控，为阐明甲基戊酸盐在拟南芥中的调控分子机制提供了基础。
In eukaryotes, all isoprenoid compounds share a common precursor, mevalonic acid, whose synthesis is catalyzed by the enzyme 3‐hydroxy‐3‐methylglutaryl coenzyme A (HMG CoA) reductase. As one step towards a better understanding of the role that this enzyme plays in coodinating isoprenoid biosynthesis in plants,Arabidopsis thalianaHMG CoA reductase was ectopically expressed in transgenicArabidopsisplants. By using this molecular genetic approach, several novel and fundamental observations have been made regarding isoprenoid biosynthesis inArabidopsis. First, it was demonstrated that the over‐expression of authenticArabidopsisHMG CoA reductase is not sufficient to alter the bulk synthesis and accumulation of the abundant end products of the plant isoprenoid pathway. Second, active transcription of the transgene appears to co‐activate and deregulate expression of the native gene, resulting in a striking elevation of HMG CoA reductase mRNA levels. Finally, although very high levels of HMG CoA reductase mRNA were expressed in these transgenic plants, only modest increases in enzyme activity could be detected. Taken together, these data suggest that HMG CoA reductase expression is regulated at multiple levels in plants as well as animals, and they provide a foundation for elucidating the molecular mechanisms for mevalonate regulation inA.thaliana.