Bone morphogenetic protein 2 (BMP2) mediates spermatogenesis in Chinese mitten crab Eriocheir sinensis by regulating kinesin motor KIFC1 expression

Functional Study of PTSMAD4 in the Spermatogenesis of the Swimming Crab Portunus trituberculatus

Portunus trituberculatus holds significant economic value. The spermatogenesis is regulated by numerous signaling pathways. Among them, the TGF-β signaling pathway plays an important role in the development of testes and spermatogenesis. Smad4 is a Co-Smad protein that forms a complex with R-Smad to regulate the expression of target genes. The sperm structure in crustaceans differs greatly from that in mammals, with mature sperm lacking tails. Our previous studies have reported the function of R-Smad in the spermatogenesis of P. trituberculatus. In this study, we cloned the full-length cDNA sequence of PTSMAD4; immunofluorescence technology revealed that PTSMAD4 is expressed throughout all stages of spermatogenesis. We knocked down the expression of PTSMAD4 in P. trituberculatus using RNAi technology, and the immunofluorescence results show abnormal co-localization and weakened signals of PTSMAD4 and PTSMAD2. Additionally, transcriptome sequencing results enriched functional genes and pathways related to spermatogenesis. This study indicates that PTSMAD4 may participate in the spermatogenesis process through its involvement in signal transduction. This research not only lays the foundation for further study of the function of the TGF-β signaling pathway in spermatogenesis but also provides a theoretical basis for further investigation of the spermatogenesis mechanism in crustaceans.

Sperm acrosomal released proteome reveals MDH and VDAC3 from mitochondria are involved in acrosome formation during spermatogenesis in Eriocheir sinensis

Acrosome is inextricably related to membranous organelles. The origin of acrosome is still controversial, one reason is that limited articles were reported about the proteomic analysis of the acrosome. Mitochondrial proteins were found exist in the acrosome, nevertheless, only limited attention has been paid to the function of mitochondrial proteins in the acrosome formation. Eriocheir sinensis sperm has a large acrosome, which makes it an ideal model to study acrosome formation. Here, we firstly compared the rate of acrosome reaction induced by the calcium ionophore A23187 and ionomycin. The rate of acrosome reaction induced by ionomycin is higher (95.8%) than A23187 (58.7%). Morphological changes were observed using light, confocal and transmission electron microscopy. Further more, proteins released during the acrosome reaction as induced by ionomycin were collected for LC-MS/MS analysis. A total of 945 proteins, including malate dehydrogenase (MDH) and voltage-dependent anion channel 3 (VDAC3), were identified in the acrosomal released proteome. The number of proteins from mitochondria (17.57%) was higher compared with endoplasmic reituculum (1.59%) and lysosomes (1.8%). To investigate the functions of target mitochondrial proteins during spermatogenesis, poly-antibodies of MDH in E. sinensis were prepared. The characteristics, further analyzed using immunofluorescence, of two mitochondrial proteins during acrosome formation showed that MDH and VDAC3 were independently involved in the formation of acrosomal membrane. These findings illustrate the acrosomal released proteome and provide important data resource for understanding the relationship between mitochondria and the acrosome in Decapoda crustacean.

Dynamic cellular and molecular characteristics of spermatogenesis in the viviparous marine teleost Sebastes schlegelii†

Spermatogenesis is a dynamic cell developmental process that is essential for reproductive success. Vertebrates utilize a variety of reproductive strategies, including sperm diversity, and internal and external fertilization. Research on the cellular and molecular dynamic changes involved in viviparous teleost spermatogenesis, however, is currently lacking. Here, we combined cytohistology, 10 × genomic single-cell RNA-seq, and transcriptome technology to determine the dynamic development characteristics of the spermatogenesis of Sebastes schlegelii. The expressions of lhcgr (Luteinizing hormone/Choriogonadotropin receptor), fshr (follicle-stimulating hormone receptor), ar (androgen receptor), pgr (progesterone receptor), and cox (cyclo-oxygen-ase), as well as the prostaglandin E and F levels peaked during the maturation period, indicating that they were important for sperm maturation and mating. Fifteen clusters were identified based on the 10 × genomic single-cell results. The cell markers of the sub-cluster were identified by their upregulation; piwil, dazl, and dmrt1 were upregulated and identified as spermatogonium markers, and sycp1/3 and spo11 were identified as spermatocyte markers. For S. schlegelii, the sperm head nucleus was elongated (spherical to streamlined in shape), which is a typical characteristic for sperm involved in internal fertilization. We also identified a series of crucial genes associated with spermiogenesis, such as spata6, spag16, kif20a, trip10, and klf10, while kif2c, kifap3, fez2, and spaca6 were found to be involved in nucleus elongation. The results of this study will enrich our cellular and molecular knowledge of spermatogenesis and spermiogenesis in fish that undergo internal fertilization.

Identification and functional analysis of Tex11 and Meig1 in spermatogenesis of Hyriopsis cumingii

Abstract: The process of spermatogenesis is complex and controlled by many genes. In mammals, Testis-expressed gene 11 (Tex11) and meiosis expressed gene 1 (Meig1) are typical spermatogenesis-related genes. In this study, we obtained the full length cDNAs for Tex11 (3143bp) and Meig1 (1649bp) in Hyriopsis cumingii by cloning. Among them, Hc-Tex11 contains 930 amino acids and Hc-Meig1 contains 91 amino acids. The protein molecular masses (MW) of Hc-Tex11 and Hc-Meig1 were 105.63 kDa and 10.95 kDa, respectively. Protein secondary structure analysis showed that Hc-TEX11 protein has three TPR domains. The expression of Hc-Tex11 and Hc-Meig1 in different tissues showed higher levels in testes. At different ages, the expression of Hc-Tex11 and Hc-Meig1 was higher levels in 3-year-old male mussels. During spermatogenesis, the mRNA levels of Hc-Tex11, Hc-Meig1 gradually increased with the development of spermatogonia and reached a peak during sperm maturation. Hc-Tex11 and Hc-Meig1 mRNA signals were detected on spermatogonia and spermatocytes by in situ hybridization. In addition, RNA interference (RNAi) experiments of Hc-Tex11 caused a down-regulated of Dmrt1, KinaseX, Tra-2 and Klhl10 genes and an up-regulated of β-catenin gene. Based on the above experimental results, it can be speculated that Hc-Tex11 and Hc-Meig1 are important in the development of the male gonadal and spermatogenesis in H. cumingii, which can provide important clues to better comprehend the molecular mechanism of Tex11 and Meig1 in regulating spermatogenesis of bivalves.