Expression pattern of enzymes related to juvenile hormone metabolism in the silkworm, Bombyx mori L.
The physiological balance of juvenile hormone (JH) in insects depends on its biosynthesis and degradation pathway. Three key enzymes namely, juvenile hormone esterase (JHE), juvenile hormone epoxide hydrolase (JHEH) and juvenile hormone diol kinase (JHDK) are required for degradation in insects. Our present results showed that JHE and JHEH exhibited expression in almost all the tissues. This indicated that JHE and JHEH might degrade JH simultaneously. In addition, the highest levels of JHDK were observed in the midgut, with trace level being found in the malpighian tubule and haemocytes. Since the midgut is a digestive organ and not a JH target, it was hypothesized that both JHE and JHEH hydrolyzed JH to JH diol (JHd) which was then transported to midgut and hydrolyzed further by JHDK, to be finally excreted out of the body. Also the expression studies on JH degradation enzymes in different tissues and stages indicated that the activities of the three enzymes are specific and coincident with the JH functions in silkworm, Bombyx mori L.
Key Laboratory of Animal Epidemic Etiology & Immunological Prevention of Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou 310029, People's Republic of China.
Yang
Y
Hua-Jun
Zhou
Z
Fang
Sabhat
S
Awquib
Firdose Ahmad
FA
Malik
Bhaskar
B
Roy
Li
L
Xing-Hua
Hu
H
Jia-Biao
Sun
S
Chun-Guang
Yan-Shan
YS
Niu
Miao
M
Yun-Gen
D000818:Animals; D012831:Bombyx / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D004851:Epoxide Hydrolases / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D007605:Juvenile Hormones / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D007605:Juvenile Hormones; D012333:RNA, Messenger; D017853:Phosphotransferases (Alcohol Group Acceptor); C460370:juvenile hormone diol kinase; D002265:Carboxylic Ester Hydrolases; C038003:juvenile hormone esterase; D004851:Epoxide Hydrolases; C055698:juvenile hormone epoxide hydrolase