Research On GPCRs Mining And Gonad Development Regulation Characteristics Of Sea Cucumber Based On Omics Data

Apostichopus japonicus is an important marine economic species in China.The aquaculture industry has developed rapidly,and its basic biological theory has been continuously improved.In particular,the release of the whole genome data of A.japonicus has greatly promoted the development of related biological research.Its reproductive biology is an important foundation for the development of artificial breeding technology.At the same time,its evolutionary status is special,making this field research an important part of the basic research on the regulation of animal reproductive development.G protein-coupled receptors(GPCRs)are the largest family of cell membrane receptor proteins,which are widely involved in the regulation of various physiological processes in the animal body.The molecular characteristics and functional activities of GPCRs are the key components to regulation mechanism of important physiological processes.Based on the genomic data of A.japonicus,combined with multi tissue transcriptional expression profile analysis and quantitative analysis of key gene expression,the GPCRs database of A.japonicus was predicted and constructed through the comprehensive application of bioinformatics methods,and the subtype classification and functional annotation were preliminarily completed;the GPCR genes specifically expressed in female and male gonads were compared and analyzed,and the molecular pathways involved in the regulation of gonad development ofA.japonicus were initially clarified;the functional genes specifically expressed in the gonads of sea cucumbers were comprehensively analyzed,and through functional enrichment and molecular pathway enrichment analysis,It is clear that the functional genes related to the "DNA replication" and "purine metabolism" pathways-play an important role in the development of the ovary and testis.From the perspective of bioinformatics analysis,the GPCRomics database of A.japonicus has been established,and the prediction information of GPCR and functional genes related to reproductive regulation has been obtained,which provides a basic reference for further in-depth research on regulation mechanisms of reproductive development and gender differentiation.The main findings are as follows:1.Based on the genomic data,GPCRs prediction and classification of A.japonicus was carried out.According to the sequence domain,sequence similarity and phylogenetic evolution,GPCRs of A.japonicus was fully mined,and subtype classification and functional annotation were completed.356 rhodopsin-like receptors(Class A),89 secretin-like receptors(Class B),25 metabotropic glutamate/pheromone receptors(Class C),4 frizzled/smoothened receptors(Class F),13 other GPCRs were obtained.The subtype classification analysis shows that Class A can be classified into 10 subfamilies;Class B and Class C are divided into four subfamilies;Class F has only one subfamily.According to the KEGG(Kyoto Encyclopedia of Genes and Genomes)database,three molecular metabolic pathways involved in GPCRs were found:"mTOR signaling pathway","Neuroactive ligand receptor interaction" and "Wnt signaling pathway".2.Using RNA-seq technology,the gonad GPCRs expression profile was constructed,and the gonad-specific GPCR functional genes were screened.The ovarian GPCR expression profile showed that 276 GPCRs were expressed in the ovary,including 7 ovary-specific GPCRs,which were adhesion,dopamine,5-hydroxytryptamine,kisspeptin,and neuropeptide CAP receptors.The testicular GPCR expression profile showed that the testis of A.japonicus expressed 245 GPCRs,including 8 testis-specific GPCRs,which were vasopressin/oxytocin,adhesion and orphan receptors.The KEGG pathway analysis showed that the gonad development of A.japonicus is controlled by three metabolic pathways,namely "mTOR signaling pathway","Neuroactive ligand-receptor interaction" and "Wnt signaling pathway".Furthermore,real-time quantitative PCR was used to analyze the influence of the screened gonad-specific GPCRs on gonadal development.The result showed that aminergic and peptide receptors could promote ovarian development in growing and mature stages respectively;PIK39302.1 receptor could promote testicular development in mature stage;and adhesion receptor could promote gonadal growth and maturation.3.Through the analysis of multi-tissue RNA-seq transcriptional expression profile data,the gonad differential genes and regulatory pathways of sea cucumber were analyzed.In the present study,643 gene structures were optimized and 15,706 genes were newly discovered;combined with difference comparison and weighted gene co-expression network analysis,941 ovarian development-related genes and 2499 testis development-related genes were identified.The GO function of ovary-and testis-specific genes was described.Further,the metabolic pathways of gonad-specific genes were analyzed,showing that 178 ovary-specific genes were annotated into 97 molecular metabolic pathways,of which 77 genes were significantly enriched,and the most enriched was "DNA replication";123 testis-specific genes were annotated into 81 molecular metabolic pathways,of which 55 genes were significantly enriched,and the most enriched was "purine metabolism".Finally,two and nine key genes related to ovarian development testicular development separately were identified by subnetwork analysis of gene interaction.This paper systematically analyzes the quantity and classification characteristics of A.japonicus GPCRs,and discusses the molecular regulation mechanism of gonadal development from the perspective of omics,which provide support for the basic theoretical research of reproductive regulation in A.japonicus and also provide an important reference for the systematic study of GPCR signal regulation mechanism in the physiological and behavioral process of A.japonicus.