Role of Halloween genes in ecdysteroids biosynthesis of the swimming crab (Portunus trituberculatus): Implications from RNA interference and eyestalk ablation.
Molting, including metamorphosis molting in arthropods are controlled by the ecdysteroids that are synthesized and secreted by the crustacean Y-organ (YO) or the insect prothoracic gland (PG). The Halloween genes encoding the enzymes mainly involved in the biosynthesis of ecdysteroids are well studied in insects but not in crustaceans. Given the importance of Halloween genes in ecdysteroids biosynthesis, we have previously reported the cDNA cloning of disembodied (Dib) in P. trituberculatus. Here, cDNA sequences of another two Halloween genes, Spook (Spo) and Shadow (Sad), were further identified and characterized. The predicted amino acid sequences for these two Halloween genes of Portunus trituberculatus were compared to those of several other arthropods, and several typical domains of the cytochrome P450 mono-oxygenase (CYP) were identified. Similar to the tissue distribution of Dib, the Spo and Sad also showed high specificity to the YO. RNA interference (RNAi) of these 3 genes indicated they all play essential role in ecdysteroids biosynthesis. To investigate the relationships of the Halloween genes to the eyestalk neuropeptides such as molt-inhibiting hormone (MIH), effects of eyestalk ablation (ESA) on the expression of Dib, Spo and Sad were detected. Expression of Dib and Sad, but not Spo, was significantly induced by ESA. The result indicated that the inhibition of MIH in ecdysteroids biosynthesis may be partly through the transcriptional regulation of certain Halloween genes, such as Dib and Sad, while the Spo might not be the target for MIH signal.
School of Marine Science, Ningbo University, 315211 Ningbo, China.
Xi
X
Xie
School of Marine Science, Ningbo University, 315211 Ningbo, China.
Zhiye
Z
Liu
School of Marine Science, Ningbo University, 315211 Ningbo, China.
Mingxin
M
Liu
School of Marine Science, Ningbo University, 315211 Ningbo, China.
Tian
T
Tao
School of Marine Science, Ningbo University, 315211 Ningbo, China.
Xiquan
X
Shen
School of Marine Science, Ningbo University, 315211 Ningbo, China. Electronic address: zhudongfa@nbu.edu.cn.
Dongfa
D
Zhu
D055011:Ablation Techniques; D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003386:Brachyura / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D026461:Ecdysteroids / Q000096:biosynthesis*; D005123:Eye; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods*; D006458:Hemolymph / Q000378:metabolism; D007447:Invertebrate Hormones / Q000378:metabolism; D008297:Male; D010802:Phylogeny; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013550:Swimming
D060829:Arthropod Proteins; D026461:Ecdysteroids; D007447:Invertebrate Hormones; C012445:molt-inhibiting hormone
Ecdysteroids; Expression pattern; Eyestalk ablation; Halloween genes; Molting; Portunus trituberculatus; RNAi