Identification and Characterization of Hdh-FMRF2 Gene in Pacific Abalone and Its Possible Role in Reproduction and Larva Development

Abstract

FMRFamide-related peptides are neuropeptides involved in a wide range of biological processes, including reproduction and larval development. To characterize the involvement of FMRFamide in the reproduction and larval development of Pacific abalone Haliotis discus hannai, an FMRFamide cDNA (Hdh-FMRF2) was cloned from the cerebral ganglion (CG). Fluorescence in situ hybridization and qRT-PCR were performed for functional characterization. The Hdh-FMRF2 cDNA encoded 204 deduced amino acids that contained a putative signal peptide and four FaRP domains. The major population of Hdh-FMRF2 neuronal cell bodies was localized in the cortex of CG. Hdh-FMRF2 mRNA expression was significantly upregulated in CG during the mature stage of gonadal development and effective accumulative temperature (EAT) exposed abalone in both sexes. In the induced spawning event, Hdh-FMRF2 expression was significantly upregulated during spawning in males. However, no upregulation was observed in females, suggesting Hdh-FMRF2 might inhibit gamete release in female abalone. These results revealed Hdh-FMRF2 as a reproduction related peptide. Furthermore, mRNA expression in larval development suggested that this peptide was also involved in larval development during development of Pacific abalone. Collectively, this study provides evidence of possible involvement of an FMRFamide neuropeptide in the reproduction and larval development of Pacific abalone.

The genome of the simultaneously hermaphroditic snail Lymnaea stagnalis reveals an evolutionary expansion of FMRFamide-like receptors

“…Supporting this observation is the fact that many molluscan reproductive processes are regulated by RFRPs and other (neuro)peptides. As in vertebrates, separate sexed molluscs can use the same substances for regulating male and female reproductive processes, because each body only contains one sex (e.g., Octopus vulgaris 90 ; Sepia o cinalis: 89 ; Sepiella japonica: 99 ; Haliotis discus hannai: 100 ). However, the evolution of simultaneous hermaphroditism means that male and female processes must be regulated concurrently within one body (e.g., Lymnaea stagnalis, Cornu aspersum, Aplysia californica 87 ).…”

The Neuropeptide HGAP Regulates Growth, Reproduction, Metamorphosis, Tissue Damage Repair, and Response against Starvation in Pacific Abalone

“…In mollusks, the neural ganglia secrete numerous neuropeptides that regulate brain activity in response to signals. The cerebral and pleuropedal ganglia are particularly important for producing neuropeptides involved in mollusk growth and reproduction [ 2 , 3 ]. However, the activity of a neuropeptide may not be limited to growth and reproduction; it may exhibit diverse physiological functions in the organism.…”