Full-length transcriptome sequencing and comparative transcriptomic analysis to uncover genes involved in early gametogenesis in the gonads of Amur sturgeon (Acipenser schrenckii)
Abstract:Full-length transcriptome sequencing and comparative transcriptomic analysis to uncover genes involved in early gametogenesis in the gonads of Amur sturgeon (Acipenser schrenckii)
AbstractBackground: Sturgeons (Acipenseriformes) are polyploid chondrostean fish that constitute an important model species for studying development and evolution in vertebrates. To better understand the mechanisms of reproduction regulation in sturgeon, this study combined PacBio isoform sequencing (Iso-Seq) with Illumina short-read… Show more
“…The expression patterns of reproduction-related genes generally exhibit significant differences between the sexes both in the developing and developed gonads. By comparative analysis of gonad transcriptomes, many candidate genes and pathways involved in sexual or reproductive regulation and gonad maturation have been identified in silver sillago ( Sillago sihama ) [ 18 ], spotted knifejaw ( Oplegnathus punctatus ) [ 19 ], olive flounder ( Paralichthys olivaceus ) [ 20 ], yellow catfish ( Pelteobagrus fulvidraco ) [ 21 ], Amur catfish ( Silurus asotus ) [ 22 ], and Amur sturgeon ( Acipenser schrenckii ) [ 23 ]. These studies provide helpful insights into reproduction-related genes and enable the discovery of new gene candidates.…”
Diodon hystrix is a new and emerging aquaculture species in south China. However, due to the lack of understanding of reproductive regulation, the management of breeding and reproduction under captivity remains a barrier for the commercial aquaculture of D. hystrix. More genetic information is needed to identify genes critical for gonadal development. Here, the first gonadal transcriptomes of D. hystrix were analyzed and 151.89 million clean reads were generated. All reads were assembled into 57,077 unigenes, and 24,574 could be annotated. By comparing the gonad transcriptomes, 11,487 differentially expressed genes were obtained, of which 4599 were upregulated and 6888 were downregulated in the ovaries. Using enrichment analyses, many functional pathways were found to be associated with reproduction regulation. A set of sex-biased genes putatively involved in gonad development and gametogenesis were identified and their sexually dimorphic expression patterns were characterized. The detailed transcriptomic data provide a useful resource for further research on D. hystrix reproductive manipulation.
“…The expression patterns of reproduction-related genes generally exhibit significant differences between the sexes both in the developing and developed gonads. By comparative analysis of gonad transcriptomes, many candidate genes and pathways involved in sexual or reproductive regulation and gonad maturation have been identified in silver sillago ( Sillago sihama ) [ 18 ], spotted knifejaw ( Oplegnathus punctatus ) [ 19 ], olive flounder ( Paralichthys olivaceus ) [ 20 ], yellow catfish ( Pelteobagrus fulvidraco ) [ 21 ], Amur catfish ( Silurus asotus ) [ 22 ], and Amur sturgeon ( Acipenser schrenckii ) [ 23 ]. These studies provide helpful insights into reproduction-related genes and enable the discovery of new gene candidates.…”
Diodon hystrix is a new and emerging aquaculture species in south China. However, due to the lack of understanding of reproductive regulation, the management of breeding and reproduction under captivity remains a barrier for the commercial aquaculture of D. hystrix. More genetic information is needed to identify genes critical for gonadal development. Here, the first gonadal transcriptomes of D. hystrix were analyzed and 151.89 million clean reads were generated. All reads were assembled into 57,077 unigenes, and 24,574 could be annotated. By comparing the gonad transcriptomes, 11,487 differentially expressed genes were obtained, of which 4599 were upregulated and 6888 were downregulated in the ovaries. Using enrichment analyses, many functional pathways were found to be associated with reproduction regulation. A set of sex-biased genes putatively involved in gonad development and gametogenesis were identified and their sexually dimorphic expression patterns were characterized. The detailed transcriptomic data provide a useful resource for further research on D. hystrix reproductive manipulation.
“…A section of the testis at 24 M showed more obvious seminal lobules and significantly increased undifferentiated spermatogonial cells (F i g. 1 I). Morphological features of the ovaries and testes at 36 M have been previously described [ 31 ]. Fig.…”
Background
Sex differentiation can be viewed as a controlled regulatory balance between sex differentiation-related mRNAs and post-transcriptional mechanisms mediated by non-coding RNAs. In mammals, increasing evidence has been reported regarding the importance of gonad-specific microRNAs (miRNAs) in sex differentiation. Although many fishes express a large number of gonadal miRNAs, the effects of these sex-biased miRNAs on sex differentiation in teleost fish remain unknown. Previous studies have shown the exclusive and sexually dimorphic expression of miR-34b/c in the gonads of the Amur sturgeon (Acipenser schrenckii), suggesting its potential role in the sex differentiation process.
Results
Using quantitative real-time PCR (qPCR), we observed that miR-34b/c showed consistent spatiotemporal expression patterns; the expression levels significantly increased during early sex differentiation. Using in situ hybridization, miR-34c was found to be located in the germ cells. In primary germ cells in vitro, the group subjected to overexpression and inhibition of miR-34c showed significantly higher proliferation ability and lower apoptosis, respectively, compared to the corresponding control group. Luciferase reporter assays using the ar-3′UTR-psiCHECK-2 luciferase vector suggested a targeted regulatory interaction between miR-34b/c and the 3′UTR of the androgen receptor (ar) mRNA. Furthermore, miR-34b/c and ar showed negative expression patterns during early sex differentiation. Additionally, a negative feedback regulation pattern was observed between foxl2 expression in the ovaries and amh and sox9 expression in the testes during early sex differentiation.
Conclusions
This study sheds new light on the roles of miR-34b/c in gonad development of Amur sturgeon, and provides the first comprehensive evidence that the gonad-predominant microRNAs may have a major role in sex differentiation in teleost fish.
“…Cyp17a1 -like plays a critical role in Cd detoxification, and knockdown of cyp17a1 -like led to a significant increase in mortality and Cd content in Crassostrea gigas ( Tian et al, 2021 ). Cyp17a1 could be an important steroidogenesis enzyme to coordinating testosterone in probable GnRH and steroidogenesis pathways of Patinopecten yessoensis ( Zhang et al, 2020 ). The present results indicate that the expression of cyp17a1 was the highest in females.…”
The freshwater mussel Hyriopsis schlegelii is a cultured bivalve in China, and the quality of the pearls produced is affected by the type of gonads. However, because of the lack of a published genome and the complexity of sex determination, research on sex reversal and development of this species is limited. In this study, Illumina RNA-seq and PacBio Isoform Sequencing (Iso-Seq) were combined to analyze the gonads of H. schlegelii. A total of 201,481 high-quality transcripts were generated. The study identified 7,922 differentially expressed genes in three comparison group (females versus males, hermaphrodites versus females, and hermaphrodites versus males). Twenty-four genes were identified as potential sex-related genes, including sox9 and wnt4 involved in sex determination, and vtg, cyp17a1 and 17β-hsd2 involved in gonadal development. We also speculated a possible pathways for the formation of hermaphroditism in H. schlegelii. The data provide a clear view of the transcriptome for H. schlegelii gonads and will be valuable in elucidating the mechanisms of gonad development.
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