Identification and expression of nuclear receptor genes and ecdysteroid titers during nymphal development in the spider Agelena silvatica.
Ecdysteroids play an essential role in the regulation of the molting processes of arthropods. Nuclear receptors of the spider Agelena silvatica that showed high homology with other arthropods especially in the functional domains were identified, two isoforms of ecdysone receptor (AsEcRA, AsEcRB), retinoid X receptor (AsRXR) and two isoforms of E75 (AsE75A, AsE75D). AsEcR and AsRXR mRNA did not show major changes in expression but occurred throughout the third instar nymphal stage. AsE75DBD was low or non-existent at first then showed a sudden increase from D7 to D10. On the other hand, AsE75D was expressed in the first half and decreased from D6 to D10. Ecdysteroid titers showed a peak on D6 in A. silvatica third instar nymphs. LC-MS/MS analysis of the ecdysteroid peak revealed only 20-hydroxyecdysone (20E) was present. The 20E peak on D6 and increase in AsE75DBD from D7 is likely a result of ecdysteroids binding to the heterodimer formed with constant expression of the AsEcR and AsRXR receptors. These findings indicate the mechanisms regulating molting widely conserved in insects and other arthropods also similarly function in spiders.
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; Research and Development Department, Fumakilla Limited, Hatsukaichi, Hiroshima, Japan. Electronic address: yoshik0u0@gmail.com.
Yoshiko
Y
Honda
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Wataru
W
Ishiguro
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan. Electronic address: m-h-ogihara@ib.k.u-tokyo.ac.jp.
Mari H
MH
Ogihara
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan.
Hiroshi
H
Kataoka
Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan. Electronic address: taylor.de.mar.ge@u.tsukuba.ac.jp.
DeMar
D
Taylor
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D026461:Ecdysteroids / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018978:Molting / Q000235:genetics / Q000502:physiology; D009758:Nymph / Q000254:growth & development; D010802:Phylogeny; D000072417:Protein Domains; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013112:Spiders / Q000235:genetics* / Q000254:growth & development*
D018076:DNA, Complementary; D026461:Ecdysteroids; D018160:Receptors, Cytoplasmic and Nuclear
20E; E75; EcR; Ecdysone; Hormone; Molting; RXR