Juvenile hormone receptor and molecular mechanism of gene expresion

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To study the molecular mechanism of gene expression regulation by insect juvenile hormone (JH), we have analyzed JH responsive genes by mRNA Differential Display in the bean bug, Riptortus clavatus. JH analog, methoprene, was applied on the diapause female adults and extracted RNA from the fat body. We found many cDNA bands which showed differnence between JHA and solvent acetone treated animals in mRNA Differential Display. We picked up the cDNA which were induced or repressed cDNA by JH treatment. Using these cDNA we performed Northern Blot analyzes for JH or acetone treated fat body RNA,and identified two JH inducible genes (JI-1and JI-2) and three JH repressible genes (JR-! , JR-2 and JR-3). The analysis of the partial sequeces of these cDNA and data base homology search indicated that JI-1 and JI-2 had high homology to cyanoprotein-a and vitellogenin, respectively, which we have showed hemolymph storage hexamer and egg yolk protein precursor. JR-1 was showed high homology to transferrin in vertebrate and insects. On the other hand we could not find any genes which have homology to JR-2 and JR-3 and concluded these gene are novel. We cloned and sequenced full length of cDNA of JI-2 and JR-1 and analyzed the changes of mRNA level after JH tretment by NOrthern Blot analyzes. We also cloned genomic DNA and analyzed the upstream regulatory gene structure of JI-1 (CP-a), JI-2 (Vg) and JR-1 (Transferrin). Now three JH inducible and three repressible genes are available to compare the regulation of expression by JH in the same insect under the same hormonal condition.