A Putative Insulin-like Androgenic Gland Hormone Receptor Gene Specifically Expressed in Male Chinese Shrimp

Abstract

The insulin-like androgenic gland hormone (IAG) is the key regulator in crustacean male sexual differentiation. As a secreted peptide hormone, IAG might perform its biological function through interacting with the membrane receptor. However, the receptor of IAG remains unclear. In the current study, a putative IAG receptor gene (FcIAGR) was identified in Fenneropenaeus chinensis. The deduced amino acid sequence of FcIAGR contained several conserved domains of insulin-like receptor proteins, including two L domains (L1 and L2), a cysteine-rich domain, three fibronectin III domains, a transmembrane domain, and an intracellular tyrosine kinase domain. Tissue distribution and in situ hybridization analysis showed that FcIAGR was predominantly expressed in the androgenic gland and testis in male F. chinensis. Protein colocalization analysis in HEK293 cells showed that FcIAGR could colocalize with both FcIAG1 and FcIAG2, respectively. Yeast two-hybrid assay further confirmed the interactions between FcIAGR and FcIAGs. After a long-term silencing of FcIAGR with double-stranded RNA, most of the germ cells in the testis were arrested at the secondary spermatocytes, whereas those in the control developed into sperm cells. The data indicated that FcIAGR was the receptor of FcIAGs in F. chinensis. The current study provides insight into the mechanism that the insulin-like signaling pathway regulates the male sexual differentiation in Decapoda crustaceans.

Sex-Biased CHHs and Their Putative Receptor Regulate the Expression of IAG Gene in the Shrimp Litopenaeus vannamei

“…As the functional core of the axis, AG controls male sexual differentiation through secreting the sexual hormone IAG (Ventura and Sagi, 2012). We previously identified a male specific expressed IAG receptor, FcIAGR, from the shrimp F. chinensis (Guo et al, 2018). Knockdown of FcIAGR expression in a late developmental stage of shrimp retarded testis development, which provided evidence to the downstream of the "eyestalk-AG-testis" endocrine axis.…”

Transcriptomic Analysis of the Kuruma Prawn Marsupenaeus japonicus Reveals Possible Peripheral Regulation of the Ovary

“…Some of the studies have shown the existence of transcripts for putative peptide hormones in the ovary: the red swamp crayfish Procambarus clarkii (47), the Australian red-craw crayfish Cherax quadricarinatus (49), and the giant freshwater prawn Macrobrachium rosenbergii (51). In addition to the peptide/protein hormone candidates, the transcriptomic data have been exploited for the identification and characterization of peptide hormone receptors (53,54) and the elucidation of molecular pathways involved in the regulation of various biological functions (55,56). Hence, transcriptomics is an essential tool in the quest to improve our understanding of reproductive biology underlying peptide hormones and their receptors in peripheral organs such as the gonads.…”

Gonadulins, the fourth type of Insulin-related peptides in Decapods

“…It has been reported that in the penaeid Fenneropenaeus the RTK4 ortholog is exclusively expressed in the testis (Guo et al, 2018). In the SRAs analyzed here reads for RTK4 orthologs are found mostly, but not exclusively in the testes and androgenic glands.…”

“…Of course, it also remains possible that one or more of these RTKs use neither of these peptides, but yet another ligand. Within this context it is interesting that orthologs of what has been labeled RTK4 here have been shown to interact with androgenin in two different species (Aizen et al, 2016;Guo et al, 2018). In Fenneropenaeus chinensis RTK4 is exclusively expressed in males and the expression data analyzed here for the closely related P.…”

“…Although virtually complete RTK sequences could either be recovered from the databases or using Trinity on a collection of transcriptome SRAs, others were only partially identified. These sequences were combined with RTKs previously identified from Macrobrachium rosenbergii, Sagmariasus verrauxi and Fenneropenaeus sinensis (Sharabi et al, 2016;Aizen et al, 2016;Guo et al, 2018) and four RTKs from the cockroach Periplaneta americana, identified here, for the construction of a phylogenetic tree. The results confirms the existence of four different decapod RTKs and shows that decapods and insects independently evolved four paralogs ( Fig.…”