C-type allatostatin and its putative receptor from the mud crab serve an inhibitory role in ovarian development

Abstract

C-type allatostatins are a family of peptides that characterized by a conserved unblocked-PISCF in C-terminal. In insects, it is well known that C-type allatostatin has a potent inhibitory effect on juvenile hormone biosynthesis by the corpora allata. Recently, C-type allatostatin has been widely identified from crustacean species but little is known about its roles. Therefore, this study described the tissue distribution patterns of C-type allatostatin and its putative receptor in the mud crab Scylla paramamosain, and further explored its potential effect on vitellogenesis. Firstly, the cDNAs encoding C-type allatostatin (Sp-AST-C) precursor and its putative receptor (Sp-AST-CR) were isolated, respectively. Subsequently, RT-PCR results suggested that, Sp-AST-C was mainly expressed in the nervous tissue, middle gut and the heart while Sp-AST-CR had an extensive expression in the detected tissues except the eyestalk ganglion and hepatopancreas. Furthermore, the Sp-AST-C expressing cells in the cerebral ganglion were detected through in situ hybridization, it showed that Sp-AST-C was localized in cluster 6, 8 of protocerebrum, cluster 9, 10, 11 of deutocerebrum, and cluster 14, 15 of tritocerebrum. The whole-mount immunofluorescence gave a similar distribution pattern. An in vitro experiment showed that, the synthetic Sp-AST-C had no effect on the abundance of Sp-Vg in the hepatopancreas and ovary but significantly reduced the expression of Sp-VgR in the ovary in a dose-dependent manner. Furthermore, it was demonstrated that the Sp-VgR expression, Vn content, and oocyte diameter in ovary were reduced after 16-days injection of Sp-AST-C. Finally, the transcripts of Sp-AST-CR were specifically localized in the oocytes of ovary by in situ hybridization, which further revealed that the oocytes were target cells for Sp-AST-C. In conclusion, our results suggested that Sp-AST-C signaling system was involved in the regulation of ovarian development, in which Sp-AST-C might inhibit the uptake of yolk by oocytes directly and obstruct oocyte growth.

Identification of Peptides and Their GPCRs in the Peppermint Shrimp Lysmata vittata, a Protandric Simultaneous Hermaphrodite Species

“…Recent studies have found that several peptide hormones are also involved in crustacean reproduction. This includes the pigment-dispersing hormone (PDH) (6), neuroparsin (7), red pigment concentrating hormone (RPCH) (8), neuropeptide F (NPF) (9), short neuropeptide F (sNPF) (10), and allatostatin (AST) (11).…”

Role of Oxytocin/Vasopressin-Like Peptide and Its Receptor in Vitellogenesis of Mud Crab

“…Recently, crustacean female sex hormone (CFSH), isolated from the sinus gland of the blue crab Callinectes sapidus, is considered to be the female sex-determining hormone [29]. Besides in S. paramamosain, the red-pigment concentrating hormone (RPCH), secreted from the eyestalk ganglion, stimulates ovarian development, while the short neuropeptide F (sNPF) and allatostatin-C show inhibitory effect on ovarian development [30,31]. In P. pelagicus, it was reported that the PpOT/VP-like peptide could inhibit the release of steroid hormones (17β-estradiol and progesterone) in ovarian explants in vitro [19].…”

G protein-coupled receptors as candidates for modulation and activation of the chemical senses in decapod crustaceans

“…argus , its expression in LF is low compared to the brain. Liu et al [ 110 ] reported that AstC neuropeptide is expressed in the olfactory lobe of decapod crustaceans. The function of the AstC signaling in decapod OSNs and olfactory lobes is unclear, but AstC has been shown to modulate olfactory learning and pheromone sensitivity in insects [ 111 ], and influences circadian rhythm and immunity [ 112 , 113 ].…”