Control of juvenile hormone biosynthesis in Bombyx mori:: Cloning of the enzymes in the mevalonate pathway and assessment of their developmental expression in the corpora allata
Control of juvenile hormone biosynthesis in Bombyx mori:: Cloning of the enzymes in the mevalonate pathway and assessment of their developmental expression in the corpora allata
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DOI：
10.1016/j.ibmb.2007.03.008
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发表时间：
2007-08-01
影响因子：
3.8
通讯作者：
Shinoda, Tetsuro
中科院分区：
文献类型：
--
作者：
Kinjoh, Terunori;Kaneko, Yu;Shinoda, Tetsuro
我们已经分离了参与家蚕保幼激素（JH）生物合成途径的甲羟戊酸途径部分的所有酶的cDNA，即，负责从乙酰辅酶A形成法呢基二磷酸的那些。有一个单一的基因编码每个酶的这条途径，与法呢基二磷酸合酶（FPPS），我们确定了三个hornologs除外。所有这些酶，但两个几乎只在咽侧体（CA），定量RT-PCR分析表明。磷酸新戊酸激酶（MevPK）在许多组织中表达，包括CA。在24日龄，FPPS 1主要在马氏管中表达，但结构相关的FPPS 2和FPPS 3的表达主要发生在CA。由于FPPS 3转录本的丰度比FPPS 2转录本的丰度低55倍，因此预期后者在该阶段的JH生物合成中起主要作用。这些酶在CA的发育表达的研究表明，在4龄幼虫，在体外JH生物合成高的阶段，所有的成绩单的水平都很高。然而，所有的甲羟戊酸酶的成绩单下降到低水平和JH酸O-甲基转移酶（JHAMT）的成绩单消失的第3天，当CA停止JH生产后，最后的幼虫蜕皮。CA在蛹期不合成JH，与甲羟戊酸激酶、磷酸新戊酸激酶、二磷酸新戊酸激酶和异戊烯基二磷酸异构酶的有限表达以及JHANIT基因的失活相一致。只有女性CA在成年阶段产生JH，这一特征与女性中JHAMT的重新表达有关，但在男性成年CA中很少。总而言之，我们的研究结果指出，在CA的JH生物合成和大多数JH生物合成酶的表达之间的关系。(c)2007爱思唯尔有限公司版权所有。
We have isolated the cDNAs of all enzymes involved in the mevalonate pathway portion of the juvenile hormone (JH) biosynthetic pathway in Bombyx mori, i.e., those responsible for the formation of farnesyl diphosphate from acetyl-CoA. There is a single gene encoding each enzyme of this pathway, with the exception of farnesyl diphosohate synthase (FPPS), for which we identified three hornologs. All but two of these enzymes are expressed almost exclusively in the corpora allata (CA), as indicated by quantitative RT-PCR analyses. Phosphornevalonate kinase (MevPK) was expressed in many tissues, including the CA. In day 24th instars, FPPS1 expression was detected primarily in the Malpighian tubules, but expression of the structurally related FPPS2 and FPPS3 occurred mainly in the CA. Since FPPS3 transcripts were 55 times less abundant than those of FPPS2, the latter is expecied to play a major role in JH biosynthesis at this stage. Studies on the developmental expression of these enzymes in the CA showed that the levels of all transcripts were high during the 4th instar larvae, a stage at which in vitro JH biosynthesis was high. However, the transcripts of all the mevalonate enzymes declined to low levels and JH acid O-methyltransferase (JHAMT) transcript disappeared by day 3 when CA ceased JH production after the final larval molt. The CA did not synthesize JH during the pupal stage, coincident with the limited expression of mevalonate kinase, phosphornevalonate kinase, diphosphornevalonate kinase and isopentenyl diphosphate isomerase, and the inactivation of the JHANIT gene. Only female CA produced JH in the adult stage, a feature associated with the re-expression of JHAMT in female but little in male adult CA. Altogether, our results point to a relationship between JH biosynthesis and expression of most JH biosynthetic enzymes in the CA. (c) 2007 Elsevier Ltd. All rights reserved.