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Cloning and expression pattern of 3‐dehydroecdysone 3β‐reductase (3DE 3β‐reductase) from the silkworm, Bombyx mori L.
Author(s) -
Yang Huajun,
Liu Xinju,
Zhou Fang,
Hu Jiabiao,
Bhaskar Roy,
Li Xinghua,
Sun Chunguang,
Malik Firdose Ahmad,
Niu Yanshan,
Miao Yungen
Publication year - 2011
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20406
Subject(s) - bombyx mori , ecdysone , reductase , biology , bombycidae , bombyx , biochemistry , aldo keto reductase , nad+ kinase , microbiology and biotechnology , enzyme , gene
Molting in insects is regulated by molting hormones (ecdysteroids), which are also crucial to insect growth, development, reproduction, etc. Ecdysone was inactivated to 3‐dehydroecdysone (3DE) under ecdysone oxidase (EO), and followed by NAD(P)H‐dependent irreversible reduction to 3‐epiecdysteroid under 3DE 3a‐reductase. On the other hand, 3‐dehydroecdysone undergoes reversible reduction to ecdysone by 3DE 3 β ‐reductase in the hemolymph. In this article, we cloned and characterized 3‐dehydroecdysone 3 β ‐reductase (3DE 3 β ‐reductase) in the different tissues and the developing stage from the silkworm, Bombyx mori L. The B. mori 3DE 3 β ‐reductase cDNA contains an ORF 972 bp and the deduced protein sequence containing 323 amino acid residues. Analysis showed that the deduced 3DE 3 β ‐reductase belongs to the aldo‐keto reductase (AKR) superfamily, which has the NAD(P)‐binding domain, indicating that the function of 3DE 3 β ‐reductase depends on the existence of NAD(P)H. Using Escherichia coli , a high level expression of a fusion polypeptide band of approx. 40 kDa was observed. The high transcription of 3DE 3 β ‐reductase was mainly observed in the genitalia and fatty bodies in the third day of the fifth‐instar larvae, followed next in the head, epidermis, and hemocytes. The expression of 3DE 3 β ‐reductase in the early of every instar was lower than that in the late of instar. When the titer of 3DE is low, higher expression of 3DE 3 β ‐reductase is necessary to maintain the ecdysone titer in body through converting 3DE to ecdysone, while the 3DE titer is high, the expression of 3DE 3 β ‐reductase showed feedback inhibition. © 2010 Wiley Periodicals, Inc.