Molecular Mechanism of Juvenile Hormone Action

豆蝽CP-1、CP-2、CP-3和CP-4是由CPa和CPb两个不同亚基组成的六聚体蛋白。从滞育和滞育雌成虫脂肪体中提取poly（A）+RNA，构建cDNA文库。分别用抗CPa和抗CPb的抗血清筛选编码CPa和CPb的cDNA克隆。CP a和CP B cDNA插入片段（a：2217 bp，B：2163 bp）的核苷酸序列预测，CP a和CP B分别含有693和686个残基。两个CP亚基在氨基酸水平上的同源性为68.0%。同源性分析表明，CPa和CPb与昆虫的六聚体和节肢动物的血蓝蛋白有较近的同源性。本文从mRNA水平上研究了棒条圆蝽（Riptortusclavatus）的Cyanoprotein（CP）基因的表达。从第5若虫期、生殖期雌虫和雄虫以及保幼激素处理的滞育雌虫和雄虫的脂肪体中提取总RNA。以CPa和CPb亚基cDNA为探针，通过北方印迹分析RNA。还通过体外翻译分析RND。在胚胎中，两种mRNA均在第2天首先出现，然后增加。CPa mRNA在蜕皮期逐渐下降，而CPb mRNA在蜕皮末期仍有大量残留。在生殖雌虫中，CPa在羽化后第3天开始表达，然后继续增加，而在蜕皮中未检测到CPa mRNA。而CPb在生殖性昆虫中仅有微量表达。在JH处理滞育的雌性中，CP的表达从CPb向CPa转移，而处理完全抑制滞育雄性中CPa和CPb的表达。

Cyanoproteins of the bean bug, Riptortus clavatus, CP-1,2,3, and 4 are hexameric proteins composed of two different subunits, CPa and CPb. The cDNA libraries were constructed from poly (A) +RNA isolated from the fat body fromdiapause and diapause female adults. The cDNA clones encoding CPa and CPb were screened by using antisera against CPa and CPb, respectively. The nucleotide sequences of CPa and CPb cDNA inserts (a : 2217bp, b : 2163bp) predicted that CPa and CPb contain 693 and 686 residues, respectively. The identities at the level of amino acid sequence between the two CP subunits were calculated to be 68.0%. Homology search revealed that CPa and CPb were closely related to insect strage hexamers and arthropod hemocyanins. The author concluded that the hemocyanins of R.clavatus fall into the so-celled 'hexamerin' superfamily.The expression of Cyanoprotein (CP) was studied at the level of mRNA in the bean bug, Riptortus clavatus. Total RNA was extracted from the fat body of 5th nymphal stages, reproductive females and males, and juvenile hormone (JH) treated diapause females and males. The RNA was analyzed by northern blot analysis using cDNAs of CPa and CPb subunits as probes. The RND was also analyzed by in vitro translation. In the nymphs, both mRNAs appeared first on day-2 and then increased. CPa mRNA decreased to the molt while large amounts of CPb mRNA still remained at the end of the stage. In the reproductive females CPa expression was first detected on day-3 after emergence, then increased onward while no CPa mRNA was detected in the molts. As for CPb, a only trace expression was observed in the reproductive bugs. In the JH treatment to the diapause females resulted in the sift of CP expression from CPb to CPa while the treatment supressed completely the expression of both CPa and CPb in the diapause males.