A coordinated expression of biosynthetic enzymes controls the flux of juvenile hormone precursors in the corpora allata of mosquitoes.
A coordinated expression of biosynthetic enzymes controls the flux of juvenile hormone precursors in the corpora allata of mosquitoes.
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DOI：
10.1016/j.ibmb.2011.04.008
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发表时间：
2011-09
影响因子：
3.8
通讯作者：
Noriega, Fernando G.
中科院分区：
文献类型：
--
作者：
Nouzova, Marcela;Edwards, Marten J.;Mayoral, Jaime G.;Noriega, Fernando G.
保幼激素（JH）是蚊子变态和卵巢发育的关键调节因子。成年雌性埃及伊蚊显示出JH合成的发育和动态调节变化。新出现的女性有侧咽体（CA）与低生物合成活性，但他们产生大量的JH一天后，血液喂养的结果在JH合成显着减少，但CA返回到高水平的JH合成三天后。为了了解这些动态变化的分子基础，我们结合了JH途径的13种酶中的11种的转录研究和JH合成的功能分析。我们检测到高达1000倍的JH生物合成酶研究之间的CA中的mRNA水平的差异。11种JH生物合成酶在雌蚊和成蚊体内存在协同表达。所有酶转录水平的增加或减少都会导致JH合成的增加或减少;这表明转录变化至少部分地导致了观察到的JH生物合成的动态变化。通过添加外源性前体如香叶基二磷酸、法呢基二磷酸、法呢醇、法呢醛和法呢酸，CA的JH合成在体外逐渐增加。这些结果表明，这些前体的供应，而不是最后6个途径酶的活性是这些腺体中的速率限制。营养储备在JH合成的调节中起着关键作用。营养不良的女性降低了编码JH生物合成酶的基因的转录水平，并减少了JH的合成。我们的研究表明，JH的合成是由类异戊二烯的流量，这是一个复杂的相互作用的结果，前体池，酶水平和外部监管机构，如营养素和脑因子的变化的速率控制。酶水平可能需要超过最低阈值，以实现通过生物合成途径的前体净流量。在合成活性低的腺体中，类异戊二烯的通量可能受到低表达水平酶活性的限制
Juvenile hormone (JH) is a key regulator of metamorphosis and ovarian development in mosquitoes. Adult female Aedes aegypti mosquitoes show developmental and dynamically regulated changes of JH synthesis. Newly emerged females have corpora allata (CA) with low biosynthetic activity, but they produce high amounts of JH a day later; blood feeding results in a striking decrease in JH synthesis, but the CA returns to a high level of JH synthesis three days later. To understand the molecular bases of these dynamic changes we combined transcriptional studies of 11 of the 13 enzymes of the JH pathway with a functional analysis of JH synthesis. We detected up to a 1000-fold difference in the levels of mRNA in the CA among the JH biosynthetic enzymes studied. There was a coordinated expression of the 11 JH biosynthetic enzymes in female pupae and adult mosquito. Increases or decreases in transcript levels for all the enzymes resulted in increases or decreases of JH synthesis; suggesting that transcript changes are at least partially responsible for the dynamic changes of JH biosynthesis observed. JH synthesis by the CA was progressively increased in vitro by addition of exogenous precursors such as geranyl-diphosphate, farnesyl-diphosphate, farnesol, farnesal and farnesoic acid. These results suggest that the supply of these precursors and not the activity of the last 6 pathway enzymes is rate limiting in these glands. Nutrient reserves play a key role in the regulation of JH synthesis. Nutritional deficient females had reduced transcript levels for the genes encoding JH biosynthetic enzymes and reduced JH synthesis. Our studies suggest that JH synthesis is controlled by the rate of flux of isoprenoids, which is the outcome of a complex interplay of changes in precursor pools, enzyme levels and external regulators such as nutrients and brain factors. Enzyme levels might need to surpass a minimum threshold to achieve a net flux of precursors through the biosynthetic pathway. In glands with low synthetic activity, the flux of isoprenoids might be limited by the activity of enzymes with low levels of expression
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DOI：
10.1016/0020-1790(84)90043-x
发表时间：
1984-01-01
期刊：
INSECT BIOCHEMISTRY
影响因子：
--
作者：
FEYEREISEN, R;RUEGG, RP;TOBE, SS
通讯作者：
TOBE, SS
影响因子：
2.9
作者：
FEYEREISEN, R;TOBE, SS
通讯作者：
TOBE, SS
影响因子：
4.1
作者：
CASCANTE, M;MELENDEZHEVIA, E;KACSER, H
通讯作者：
KACSER, H
影响因子：
2.2
作者：
SHAPIRO, AB;WHEELOCK, GD;SCHOOLEY, DA
通讯作者：
SCHOOLEY, DA
影响因子：
2.2
作者：
Hernandez-Martinez, Salvador;Mayoral, Jaime G.;Noriega, Fernando G.
通讯作者：
Noriega, Fernando G.