Liu A, Liu F, Shi W, Huang H, Wang G, Ye H. C-Type allatostatin and its putative receptor from the mud crab serve an inhibitory role in ovarian development.
ACTA ACUST UNITED AC 2019;
222:jeb.207985. [PMID:
31558587 DOI:
10.1242/jeb.207985]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 09/23/2019] [Indexed: 01/02/2023]
Abstract
C-Type allatostatins are a family of peptides that characterized by a conserved unblocked PISCF motif at the C-terminus. In insects, it is well known that C-type allatostatin has a potent inhibitory effect on juvenile hormone biosynthesis by the corpora allata. C-Type allatostatin has been widely identified from crustacean species but little is known about its roles. Therefore, this study investigated 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, cDNAs encoding C-type allatostatin (Sp-AST-C) precursor and its putative receptor (Sp-AST-CR) were isolated. Subsequently, RT-PCR revealed that Sp-AST-C was mainly expressed in the nervous tissue, middle gut and heart, whereas Sp-AST-CR had extensive expression in all tissues tested except the eyestalk ganglion and hepatopancreas. In addition, in situ hybridization in the cerebral ganglion showed that Sp-AST-C was localized in clusters 6 and 8 of the protocerebrum, clusters 9, 10 and 11 of the deutocerebrum, and clusters 14 and 15 of the tritocerebrum. Whole-mount immunofluorescence revealed a similar distribution pattern. Synthetic Sp-AST-C had no effect on the abundance of S. paramamosain vitellogenin (Sp-Vg) in the hepatopancreas and ovary in vitro but significantly reduced the expression of its receptor (Sp-VgR) in the ovary in a dose-dependent manner. Furthermore, Sp-VgR expression, vitellin content and oocyte diameter in the ovary were reduced 16 days after the first injection of Sp-AST-C. Finally, in situ hybridization showed that Sp-AST-CR transcript was specifically localized in the oocytes, which further indicated that the oocytes are the target cells for Sp-AST-C. In conclusion, our results suggested that the Sp-AST-C signaling system is involved in the regulation of ovarian development, possibly by directly inhibiting the uptake of yolk by oocytes and obstructing oocyte growth.
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