RRC ID 6089
Author Niwa R, Namiki T, Ito K, Shimada-Niwa Y, Kiuchi M, Kawaoka S, Kayukawa T, Banno Y, Fujimoto Y, Shigenobu S, Kobayashi S, Shimada T, Katsuma S, Shinoda T.
Title Non-molting glossy/shroud encodes a short-chain dehydrogenase/reductase that functions in the 'Black Box' of the ecdysteroid biosynthesis pathway.
Journal Development
Abstract In insects, the precise timing of molting and metamorphosis is strictly guided by a principal steroid hormone, ecdysone. Among the multiple conversion steps for synthesizing ecdysone from dietary cholesterol, the conversion of 7-dehydrocholesterol to 5beta-ketodiol, the so-called 'Black Box', is thought to be the important rate-limiting step. Although a number of genes essential for ecdysone synthesis have recently been revealed, much less is known about the genes that are crucial for functioning in the Black Box. Here we report on a novel ecdysteroidgenic gene, non-molting glossy (nm-g)/shroud (sro), which encodes a short-chain dehydrogenase/reductase. This gene was first isolated by positional cloning of the nm-g mutant of the silkworm Bombyx mori, which exhibits a low ecdysteroid titer and consequently causes a larval arrest phenotype. In the fruit fly, Drosophila melanogaster, the closest gene to nm-g is encoded by the sro locus, one of the Halloween mutant members that are characterized by embryonic ecdysone deficiency. The lethality of the sro mutant is rescued by the overexpression of either sro or nm-g genes, indicating that these two genes are orthologous. Both the nm-g and the sro genes are predominantly expressed in tissues producing ecdysone, such as the prothoracic glands and the ovaries. Furthermore, the phenotypes caused by the loss of function of these genes are restored by the application of ecdysteroids and their precursor 5beta-ketodiol, but not by cholesterol or 7-dehydrocholesterol. Altogether, we conclude that the Nm-g/Sro family protein is an essential enzyme for ecdysteroidogenesis working in the Black Box.
Volume 137(12)
Pages 1991-9
Published 2010-6-1
DOI 10.1242/dev.045641
PII 137/12/1991
Description nm-g(光沢不眠蚕)の原因遺伝子はnm-g/sroである。nm-g/sroは短鎖型脱水素・還元酵素をコードし、エクジステロイドの生合成を制御する。a46系統(nm-g/nm-g)では、nm-g/sroのエクソン3に5.2 kbのnon-LTR型トランスポゾンが挿入されている。
PMID 20501590
MeSH Animals Bombyx / enzymology Bombyx / genetics Bombyx / metabolism Dehydrocholesterols / metabolism* Drosophila melanogaster / enzymology Drosophila melanogaster / genetics Drosophila melanogaster / metabolism Ecdysone / biosynthesis* Ecdysone / genetics Ecdysone / metabolism Ecdysteroids / biosynthesis* Ecdysteroids / genetics Ecdysteroids / metabolism Molting / genetics* Oxidoreductases / genetics* Oxidoreductases / metabolism
IF 5.611
Times Cited 107
Silkworms a46