Insights Into Sexual Maturation and Reproduction in the Norway Lobster (Nephrops norvegicus) via in silico Prediction and Characterization of Neuropeptides and G Protein-coupled Receptors

Abstract

Multiple biological processes across development and reproduction are modulated by neuropeptides that are predominantly produced and secreted from an animal's central nervous system. In the past few years, advancement of next-generation sequencing technologies has enabled large-scale prediction of putative neuropeptide genes in multiple non-model species, including commercially important decapod crustaceans. In contrast, knowledge of the G protein-coupled receptors (GPCRs), through which neuropeptides act on target cells, is still very limited. In the current study, we have used in silico transcriptome analysis to elucidate genes encoding neuropeptides and GPCRs in the Norway lobster (Nephrops norvegicus), which is one of the most valuable crustaceans in Europe. Fifty-seven neuropeptide precursor-encoding transcripts were detected, including phoenixin, a vertebrate neurohormone that has not been detected in any invertebrate species prior to this study. Neuropeptide gene expression analysis of immature and mature female N. norvegicus, revealed that some reproduction-related neuropeptides are almost exclusively expressed in immature females. In addition, a total of 223 GPCR-encoding transcripts were identified, of which 116 encode GPCR-A (Rhodopsin), 44 encode GPCR-B (Secretin) and 63 encode other GPCRs. Our findings increase the molecular toolbox of neural signaling components in N. norvegicus, allowing for further advances in the fisheries/larvae culture of this species.

Identifying Neuropeptide and G Protein-Coupled Receptors of Juvenile Oriental River Prawn (Macrobrachium nipponense) in Response to Salinity Acclimation

“…Importantly, our study was the first to indicate that certain neuropeptides in prawns play an important role in response to salinity acclimation. Interestingly, some neuropeptide transcripts that were detected previously in other decapod crustacean species were not identified in this M. nipponense transcriptome, such as crustacean female sex hormone (CFSH) (27,28). Notably, our previous M. nipponense de novo transcriptome assembly did include these neuropeptides, which partially disagrees with the results of the present study.…”

Multi-Tissue Transcriptome Analysis Identifies Key Sexual Development-Related Genes of the Ornate Spiny Lobster (Panulirus ornatus)

“…In another parallel with vertebrates, it is yet to be elucidated whether the arthropod ILPs function as relaxins, while the GPA2/B5 receptor is from the same family of LRR GPCRs. With regard to the expression of these putative GSHs and their cognate receptors, RPCH and its receptor are strictly expressed in the neural tissues, while GPB5 is also expressed in the ovary across species, whereas GPA2 is not [ 5 , 9 , 66 ]. Since both GPA2 and GPB5 are coexpressed in the neural tissues, they could potentially dimerize and then act on the gonad, whereas, in the gonad itself, only GPB5 is expressed, which could regulate the function of dimerized factors from the CNS.…”

“…Over the past decade, transcriptomic libraries have identified a wealth of genes exhibiting sexually dimorphic expression across many animal species. In decapod crustaceans, a refined list of genes related to sexual development was elucidated, with some that have clear roles and some that are yet to be defined [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. While the sex determination cascade is highly variable, a widely conserved element has been the family of “doublesex- and male abnormal (MAB)-3-related transcription factors” (Dmrts).…”

Crustacean vitellogenin: a systematic and experimental analysis of their genes, genomes, mRNAs and proteins; and perspective to Next Generation Sequencing

“…Regardless of the presence of one or two Vtg transcripts, their expression is strictly related to the oogenic cycle , and Vtg levels in the haemolymph are often indicative of ovarian development (Thongda et al, 2015). For most crustacean species, ovarian development is separated into four stages (Nguyen et al, 2018) and external conditions are intimately connected with ovarian maturation, depending mostly on the season of the year, with maximum reproduction peaks in seasons with higher temperatures (Thongda et al, 2015).…”