Mammalian Spermatogenesis Research Articles

CARF regulates the alternative splicing and piwi/piRNA complexes during mouse spermatogenesis through PABPC1.

ADP-ribosylation factor collaborator (CARF), which is also known as CDKN2AIP, was first recognized as an ADP-ribosylation factor-interacting protein that participates in the activation of the ARF-p53-p21 (WAF1) signaling pathway under different conditions, such as oxidative and oncogenic stresses. The activation of this pathway often leads to cell growth arrest and apoptosis as well as senescence. Previous studies revealed that CARF, an RNA-binding protein, is critical for maintaining stem cell pluripotency and somatic differentiation. Nevertheless, its involvement in spermatogenesis has not been well examined. In this study, we show that male mice deficient in Carf expression present impaired spermatogenesis and fertility. IP-MS and RNA-seq analyses reveal that CARF/ Carf interacts with multiple key splicing factors, such as PABPC1, and directly targets 356 different types of mRNAs in spermatocytes. Carf-associated mRNAs display aberrant splicing patterns when Carf expression is deficient. In addition, our results demonstrate that PIWIL1 expression and localization are altered in the Carf -/ - mouse model through the downregulation of PABPC1, which further affects the ratio of pachytene-piRNA. Our study suggests that CARF is critical for regulating alternative splicing in mammalian spermatogenesis and determining infertility in male mice.

Integrated Quantitative Proteomics and Phosphoproteomics Analysis Reveals the Dynamic Process of Buffalo (Bubalus bubalis) Spermatogenesis.

Spermatogenesis is a highly complex and tightly regulated cellular differentiation process closely related to the productive performance of male livestock. We do not yet have a clear understanding of the spermatogenesis mechanism of buffalo. In this study, spermatogonia, spermatocytes and spermatids were analysed by flow cytometry. Quantitative proteomic and phosphoproteomic studies were performed on different spermatogenic cells using tandem mass tagging technology and liquid chromatography-tandem mass spectrometry. A total of 219 differentially expressed proteins (involved in focal adhesions and actin cytoskeleton pathways) and 71 phosphoproteins (involved in RNA transport and adhesion junction pathways) were obtained. Through trend analysis, a dynamic profile of protein expression was obtained, enriched to the main biological processes at different stages of spermatogenesis. By immunohistochemical localisation analysis, it was found that MACROH2A2, TOP2A, LMNA, LMNA (pS392), VIM and VIM (pS56) had specific localisation in testis cells. Network analysis of kinase-substrate phosphorylation sites showed that AKT1 is the most active kinase, LMNA is regulated by most kinases and AKT1 can catalyse the phosphorylation of LMNA. This study provides a reference for studying the molecular mechanism of buffalo spermatogenesis and helps clarify the regulatory mechanism of protein translation and post-translational modification during mammalian spermatogenesis.

Can Mammalian Reproductive Health Withstand Massive Exposure to Polystyrene Micro- and Nanoplastic Derivatives? A Systematic Review.

The widespread use of plastics has increased environmental pollution by micro- and nanoplastics (MNPs), especially polystyrene micro- and nanoplastics (PS-MNPs). These particles are persistent, bioaccumulative, and linked to endocrine-disrupting toxicity, posing risks to reproductive health. This review examines the effects of PS-MNPs on mammalian reproductive systems, focusing on oxidative stress, inflammation, and hormonal imbalances. A comprehensive search in the Web of Science Core Collection, following PRISMA 2020 guidelines, identified studies on the impact of PS-MNPs on mammalian fertility, including oogenesis, spermatogenesis, and folliculogenesis. An analysis of 194 publications revealed significant reproductive harm, such as reduced ovarian size, depleted follicular reserves, increased apoptosis in somatic cells, and disrupted estrous cycles in females, along with impaired sperm quality and hormonal imbalances in males. These effects were linked to endocrine disruption, oxidative stress, and inflammation, leading to cellular and molecular damage. Further research is urgently needed to understand PS-MNPs toxicity mechanisms, develop interventions, and assess long-term reproductive health impacts across generations, highlighting the need to address these challenges given the growing environmental exposure.

The Intricate Functional Networks of Pre-mRNA Alternative Splicing in Mammalian Spermatogenesis.

Spermatogenesis is a highly coordinated process that requires the precise expression of specific subsets of genes in different types of germ cells, controlled both temporally and spatially. Among these genes, those that can exert an indispensable influence in spermatogenesis via participating in alternative splicing make up the overwhelming majority. mRNA alternative-splicing (AS) events can generate various isoforms with distinct functions from a single DNA sequence, based on specific AS codes. In addition to enhancing the finite diversity of the genome, AS can also regulate the transcription and translation of certain genes by directly binding to their cis-elements or by recruiting trans-elements that interact with consensus motifs. The testis, being one of the most complex tissue transcriptomes, undergoes unparalleled transcriptional and translational activity, supporting the dramatic and dynamic transitions that occur during spermatogenesis. Consequently, AS plays a vital role in producing an extensive array of transcripts and coordinating significant changes throughout this process. In this review, we summarize the intricate functional network of alternative splicing in spermatogenesis based on the integration of current research findings.

Evolutionary innovations in germline biology of placental mammals identified by transcriptomics of first-wave spermatogenesis in opossum.

Mammalian spermatogenesis is a highly stereotyped and conserved developmental process that is essential for fitness. At the same time, gene expression in spermatogenic cells is rapidly evolving. This combination of features has been suggested to drive rapid fixation of new gene expression patterns. Using a high-resolution dataset comprising bulk and single-cell data from juvenile and adult testes of the opossum Monodelphis domestica, a model marsupial, we define the developmental timing of the spermatogenic first wave in opossum and delineate conserved and divergent gene expression programs across the placental-marsupial split by comparison to equivalent data from mouse, a model placental mammal. Epigenomic data confirmed divergent regulation at the level of transcription, and comparison to data from four additional amniote species identified hundreds of genes with evidence of rapid fixation of expression. This gene set encompasses known and previously undescribed regulators of spermatogenic development.

The landscape of RNA binding proteins in mammalian spermatogenesis.

Despite continuous expansion of the RNA binding protein (RBP) world, there is a lack of systematic understanding of RBPs in the mammalian testis, which harbors one of the most complex tissue transcriptomes. We adapted RNA interactome capture to mouse male germ cells, building an RBP atlas characterized by multiple layers of dynamics along spermatogenesis. Trapping of RNA-cross-linked peptides showed that the glutamic acid-arginine (ER) patch, a residue-coevolved polyampholytic element present in coiled coils, enhances RNA binding of its host RBPs. Deletion of this element in NONO (non-POU domain-containing octamer-binding protein) led to a defective mitosis-to-meiosis transition due to compromised NONO-RNA interactions. Whole-exome sequencing of over 1000 infertile men revealed a prominent role of RBPs in the human genetic architecture of male infertility and identified risk ER patch variants.

RNA-binding protein IGF2BP1 is required for spermatogenesis in an age-dependent manner.

Post-transcriptional regulation mediated by RNA binding proteins is crucial for male germline development. Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), an RNA binding protein, is specifically expressed in human and mouse male gonads and is involved in manifold biological processes and tumorigenesis. However, the function of IGF2BP1 in mammalian spermatogenesis remains poorly understood. Herein, we generated an Igf2bp1 conditional knockout mouse model using Nanos3-Cre. Germ cell deficiency of Igf2bp1 in mice caused spermatogenic defects in an age-dependent manner, resulting in decreased numbers of undifferentiated spermatogonia and increased germ cell apoptosis. Immunoprecipitation-mass spectrometry analysis revealed that ELAV-like RNA binding protein 1, a well-recognized mRNA stabilizer, interacted with IGF2BP1. Single cell RNA-sequencing showed distinct mRNA profiles in spermatogonia from conditional knockout versus wide type mice. Further research showed that IGF2BP1 plays a vital role in the modulation of spermatogenesis by regulating Lin28a mRNA, which is essential for clonal expansion of undifferentiated spermatogonia. Thus, our results highlight the crucial effects of IGF2BP1 on spermatogonia for the long-term maintenance of spermatogenesis.

Establishment and Characterization of Testis Organoids with Proliferation and Differentiation of Spermatogonial Stem Cells into Spermatocytes and Spermatids.

Organoids play pivotal roles in uncovering the molecular mechanisms underlying organogenesis, intercellular communication, and high-throughput drug screening. Testicular organoids are essential for exploring the genetic and epigenetic regulation of spermatogenesis in vivo and the treatment of male infertility. However, the formation of testicular organoids with full spermatogenesis has not yet been achieved. In this study, neonatal mouse testicular cells were isolated by two-step enzymatic digestion, and they were combined with Matrigel and transplanted subcutaneously into nude mice. Histological examination (H&E) staining and immunohistochemistry revealed that cell grafts assembled to form seminiferous tubules that contained spermatogonial stem cells (SSCs) and Sertoli cells, as illustrated by the co-expression of PLZF (a hallmark for SSCs) and SOX9 (a marker for Sertoli cells) as well as the co-expression of UCHL1 (a hallmark for SSCs) and SOX9, after 8 weeks of transplantation. At 10 weeks of transplantation, SSCs could proliferate and differentiate into spermatocytes as evidenced by the expression of PCNA, Ki67, c-Kit, SYCP3, γ-HA2X, and MLH1. Notably, testicular organoids were seen, and spermatids were observed within the lumen of testicular organoids after 16 weeks of transplantation, as shown by the presence of TNP1 and ACROSIN (hallmarks for spermatids). Collectively, these results implicate that we successfully established testicular organoids with spermatogenesis in vivo. This study thus provides an excellent platform for unveiling the mechanisms underlying mammalian spermatogenesis, and it might offer valuable male gametes for treating male infertility.

PNLDC1 catalysis and postnatal germline function are required for piRNA trimming, LINE1 silencing, and spermatogenesis in mice.

PIWI-interacting RNAs (piRNAs) play critical and conserved roles in transposon silencing and gene regulation in the animal germline. Three distinct piRNA populations are present during mouse spermatogenesis: fetal piRNAs in fetal/perinatal testes, pre-pachytene and pachytene piRNAs in postnatal testes. PNLDC1 is required for piRNA 3' end maturation in multiple species. However, whether PNLDC1 is the bona fide piRNA trimmer and the physiological role of 3' trimming of different piRNA populations in spermatogenesis in mammals remain unclear. Here, by inactivating Pnldc1 exonuclease activity in vitro and in mice, we reveal that the PNLDC1 trimmer activity is essential for spermatogenesis and male fertility. PNLDC1 catalytic activity is required for both fetal and postnatal piRNA 3' end trimming. Despite this, postnatal piRNA trimming but not fetal piRNA trimming is critical for LINE1 transposon silencing. Furthermore, conditional inactivation of Pnldc1 in postnatal germ cells causes LINE1 transposon de-repression and spermatogenic arrest in mice, indicating that germline-specific postnatal piRNA trimming is essential for transposon silencing and germ cell development. Our findings highlight the germ cell-intrinsic role of PNLDC1 and piRNA trimming in mammals to safeguard the germline genome and promote fertility.

Prenatal exposure to environmentally relevant levels of PAHs inhibits spermatogenesis in adult mice and the mechanism involved

Polycyclic aromatic hydrocarbons (PAHs) are a class of contaminants that cannot be banned. Exposure to PAHs has been reported to alter spermatogenesis in mammals, but little is known about prenatal exposure to a mixture of PAHs on the reproductive toxicity of adult offspring. In this study, we investigated the associations between prenatal exposure to environmentally relevant levels of PAHs in mice and testicular dysfunction, including impaired spermatogenesis and steroid hormone dysfunction in male offspring on postnatal day 180. The percentage of testicular apoptotic cells was significantly increased, which was further verified by the up-regulated BAX protein. The expression of Ar and the Leydig cell marker Cyp11a1 was down-regulated, suggesting an impairment in the synthesis of steroid hormones. DNA hypermethylation of the Tnp1 and Sohlh2 promoters suppresses transcriptional expression, consequently altering the sperm production process. This study shows that prenatal exposure to PAHs may induce long-term reproductive toxicity.

Vangl2 regulates intercellular junctions by remodeling actin-based cytoskeleton through the Rock signaling pathway during spermatogenesis in Eriocheir sinensis

As a key planar cell polarity protein, Van Gogh-like 2 (Vangl2) is essential for mammalian spermatogenesis. As a decapod crustacean, Eriocheir sinensis exhibits distinct spermatogenic processes due to its unique seminiferous tubule morphology and hemolymph-testis barrier (HTB). To determine whether Vangl2 performs analogous functions in E. sinensis, we identified the Es-Vangl2. Es-Vangl2 exhibited high expression and wide distribution in the testes, indicating its crucial involvement in spermatogenesis. Following targeted knockdown of Es-Vangl2in vivo, the structure of seminiferous tubules was disrupted, characterized by vacuolization of the germinal zone and obstruction of spermatozoon release. Concurrently, the integrity of the HTB was compromised, accompanied by reduced expression and aberrant localization of junction proteins. More importantly, the regulatory influence of Es-Vangl2 was manifested through modulating the organization of microfilaments, a process mediated by epidermal growth factor receptor pathway substrate 8 (Eps8). Further studies demonstrated that these phenotypes resulting from Es-Vangl2 knockdown were attributed to the inhibition of Rock signaling pathway activity, which was verified by the Es-Rock interference and Y27632 inhibition assays. In summary, the findings highlight the pivotal role of Es-Vangl2 in stabilizing HTB integrity by regulating Eps8-mediated actin remodeling through the Rock signaling pathway in the spermatogenesis of E. sinensis.

The RNA-seq mapping of Testicular Development after Heat Stress in Sexually Mature Mice

The testis serves as the primary site for spermatogenesis in mammals and is a crucial organ for the secretion of male hormones. Heat stress (HS) can have adverse effects on the seminiferous tubules, sperm quality, and sperm fertilization capability within the testis. Despite numerous previous studies describing various time points after heat stress in mice, a systematic and comprehensive dataset on heat stress and recovery in mice has been lacking. This study aimed to explore the gene expression changes in the recovery of multiple seminiferous epithelial cycles and spermatogenic cycles in mouse testicles after heat stress. We obtained high-throughput bulk RNA-seq data from testicular tissue of 4 NC mice and 32 HS mice (divided into 9 groups: NC, 30 min, 2 h, 6 h, 24 h, 3d, 8d, 24d, 47d, and 95d) and illustrated the dynamic changes in differential genes. This data set provides valuable insights into the detailed dynamic changes of one or more spermatogenic cycles after heat stress in mouse testicles, as well as the molecular mechanisms involved.

Histone acetylation regulated by histone deacetylases during spermatogenesis.

Physical, chemical, and biological factors in the environment constantly influence in vivo and in vitro biological processes, including diverse histone modifications involved in cancer and metabolism. However, the intricate mechanisms of acetylation regulation remain poorly elucidated. In mammalian spermatogenesis, acetylation plays a crucial role in repairing double-strand DNA breaks, regulating gene transcription, and modulating various signaling pathways. This review summarizes the histone acetylation sites in the mouse testis and provides a comprehensive overview of how histone acetylation is involved in different stages of spermatogenesis under the regulation by histone deacetylases. The regulatory functions of various class histone deacetylases during spermatogenesis and the crossroad between histone acetylation and other histone modifications are highlighted. It is imperative to understand the mechanisms of histone acetylation regulated by histone deacetylases in spermatogenesis, which facilitates to prevent and treat infertility-related diseases.

The dynamic expression of YAP is essential for the development of male germ cells derived from human embryonic stem cells

YAP plays a vital role in controlling growth and differentiation in various cell lineages. Although the expression of YAP in mice testicular and spermatogenic cells suggests its role in mammalian spermatogenesis, the role of YAP in the development of human male germ cells has not yet been determined. Using an in vitro model and a gene editing approach, we generated human spermatogonia stem cell-like cells (hSSLCs) from human embryonic stem cells (hESCs) and investigated the role of YAP in human spermatogenesis. The results showed that reducing YAP expression during the early stage of spermatogenic differentiation increased the number of PLZF+ hSSLCs and haploid spermatid-like cells. We also demonstrated that the up-regulation of YAP is essential for maintaining spermatogenic cell survival during the later stages of spermatogenic differentiation. The expression of YAP that deviates from this pattern results in a lower number of hSSLCs and an increased level of spermatogenic cell death. Taken together, our result demonstrates that the dynamic expression pattern of YAP is essential for human spermatogenesis. Modulating the level of YAP during human spermatogenesis could improve the production yield of male germ cells derived from hESCs, which could provide the optimization method for in vitro gametogenesis and gain insight into the application in the treatment of male infertility.

P-523 Single molecule chromatin footprinting reveals only low occurrence of nucleosomes at multiple loci throughout chromatin of human and mouse spermatozoa

Abstract Study question What fraction of spermatozoa from mouse and human semen contain nucleosomes at specific loci? What chromatin features affect nucleosome retention in spermatozoa? Summary answer On average, 1-2% mouse spermatozoa and 5-9% human spermatozoa contain nucleosomes at sampled genomic loci, with moderately higher frequencies at unmethylated regions of DNA. What is known already Nucleosomes constitute the basic packaging and gene regulatory unit of DNA in eukaryotic cells. During final stages of spermatogenesis in mammals, however, most nucleosomes are replaced by protamines. Previous global chromatin immunoprecipitation-sequencing studies reported the presence of nucleosomes at gene regulatory and other genomic regions. Such nucleosomes were proposed to convey intergenerational inheritance of epigenetic information. Additional studies revealed that infertile men with decreased success of assisted reproductive therapy have protamine deficiency or displayed more widely distributed nucleosomes in their sperm genome. Direct links between altered levels of nuclear proteins and fertilizing potential of sperm have, however, not been established. Study design, size, duration We conducted a case study on nucleosome retention levels in sperm from four selected fertile human samples. This study was complemented in mice, in which we characterized the dynamic changes in nucleosome frequencies at genomic loci during differentiation of haploid spermatids into spermatozoa, and their responses in mutant spermatozoa lacking DNA methylation at certain loci. Participants/materials, setting, methods We used the single-molecule sequencing technique called Nucleosome Occupancy and Methylome Sequencing to quantify nucleosome occupancy rates at selected loci in spermatozoa from ejaculated semen of four fertile semen donors. We also profiled round spermatids, early and late elongating spermatids and spermatozoa of C57BL/6J wild-type mice as well as spermatozoa of mice conditionally deficient for the methyltransferases Dnmt3a and Dnmt3b, lacking DNA methylation at certain genomic regions. Main results and the role of chance To our knowledge, this is the first study to quantify nucleosome occupancy in mouse male gametes and human spermatozoa at single-molecule resolution. In mice, we observed that chromatin remodelling during spermatid elongation resulted in a progressive loss of nucleosomes and their positioning, a transient gain in global chromatin accessibility which was succeeded by increasing chromatin inaccessibility and nuclear compaction. In both human and mouse sperm, we profiled nucleosome occupancy levels at different genomic loci and measured only low percentages, ranging from ∼1-2% in mouse and 5-9% in human. In both organisms we observed a near two-fold higher nucleosome occupancy at loci being unmethylated at their DNA over loci being highly methylated. Mice partially deficient in genomic DNA methylation manifested a similar fold increase in nucleosome occupancy in absence of DNA methylation. These data reveal a moderate modulatory role for DNA methylation established in spermatogonial stages in regulating nucleosome eviction during spermiogenesis. The overall low nucleosome occupancy frequencies in mammalian spermatozoa suggest a stochastic or random rather than a programmed role of nucleosomes in regulating paternal gene expression during ensuing embryonic development. Limitations, reasons for caution Amplicon-based sequencing provides deep sequencing coverage for selected genomic loci. We lack, however, information on the distribution of nucleosomes among loci within the genome of single spermatozoa. In human, we studied a limited number of human donors. Wider implications of the findings This study resolves a long-standing question on the frequency and local distribution of nucleosomes in murine and human spermatozoa. The variability in nucleosome occupancy between spermatozoa within and between samples of human individuals inspires further investigations into the relationship between chromatin states and quality of individual spermatozoa for embryonic development. Trial registration number SNCTP000003654

DIS3 ribonuclease is essential for spermatogenesis and male fertility in mice.

Spermatogonial stem cell (SSC) self-renewal and differentiation provide foundational support for long-term, steady-state spermatogenesis in mammals. Here, we have investigated the essential role of RNA exosome associated DIS3 ribonuclease in maintaining spermatogonial homeostasis and facilitating germ cell differentiation. We have established male germ-cell Dis3 conditional knockout (cKO) mice in which the first and subsequent waves of spermatogenesis are disrupted. This leads to a Sertoli cell-only phenotype and sterility in adult male mice. Bulk RNA-seq documents that Dis3 deficiency partially abolishes RNA degradation and causes significant increases in the abundance of transcripts. This also includes pervasively transcribed PROMoter uPstream Transcripts (PROMPTs), which accumulate robustly in Dis3 cKO testes. In addition, scRNA-seq analysis indicates that Dis3 deficiency in spermatogonia significantly disrupts RNA metabolism and gene expression, and impairs early germline cell development. Overall, we document that exosome-associated DIS3 ribonuclease plays crucial roles in maintaining early male germ cell lineage in mice.

Investigating the potential of X chromosome shredding for mouse genetic biocontrol

CRISPR-Cas9 technology has facilitated development of strategies that can potentially provide more humane and effective methods to control invasive vertebrate species, such as mice. One promising strategy is X chromosome shredding which aims to bias offspring towards males, resulting in a gradual and unsustainable decline of females. This method has been explored in insects with encouraging results. Here, we investigated this strategy in Mus musculus by targeting repeat DNA sequences on the X chromosome with the aim of inducing sufficient DNA damage to specifically eliminate X chromosome-bearing sperm during gametogenesis. We tested three different guide RNAs (gRNAs) targeting different repeats on the X chromosome, together with three male germline-specific promoters for inducing Cas9 expression at different stages of spermatogenesis. A modest bias towards mature Y-bearing sperm was detected in some transgenic males, although this did not translate into significant male-biasing of offspring. Instead, cleavage of the X chromosome during meiosis typically resulted in a spermatogenic block, manifest as small testes volume, empty tubules, low sperm concentration, and sub/infertility. Our study highlights the importance of controlling the timing of CRISPR-Cas9 activity during mammalian spermatogenesis and the sensitivity of spermatocytes to X chromosome disruption.

Research progress on the role of lycopene in promoting mammalian spermatogenesis

A carotenoid called lycopene (LYC) is one of the most potent antioxidants. Superior physiological properties of LYC include cancer prevention, cholesterol reduction, antioxidant activity, scavenging of free radicals, immunity enhancement, prostate protection, and increased sperm viability. In recent times, male sperm quality has decreased. Following studies on LYC’s function in spermatogenesis, the therapy of male infertility diseases has made extensive use of it. Here, we give an accurate theoretical foundation for the use of LYC in large animal breeding and the treatment of male infertility in humans by summarising the variables influencing spermatogenesis and the enhancing effect of LYC on mammalian spermatogenesis.

Functional regulation of testosterone underlying state transition in seasonal spermatogenesis of Plateau Pika (Ochotona curzoniae)

Abstract Seasonal reproduction is an adaptive strategy that benefits the survival and growth of offspring. However, the regulatory mechanisms affecting spermatogenesis in male seasonal breeders are not well understood. We examined the actions of testosterone on seasonal spermatogenesis of Plateau Pika (Ochotona curzoniae), a typical long-day breeder living on the Qinghai–Tibetan Plateau. The annual dynamics of germ cell development and steroid hormone synthesis were confirmed and were consistent with testicular morphology. Furthermore, a testosterone regulation experiment showed that elevated testosterone stimulated proliferation of spermatogonia and regeneration of advanced spermatogenic cells in reproductively dormant pika, while testosterone suppression induced cell apoptosis both in reproductively active and dormant pikas. Transcriptomic analyses indicated that testosterone-regulated genes related to spermatogonial fate determination by binding to androgen receptors and inducing the production of retinoic acid, which was responsible for the initiation of spermatogonial differentiation. We show that testosterone orchestrates downstream signaling pathways to balance spermatogonial self-renewal and development. These findings provide a new perspective on seasonal regulation of mammalian spermatogenesis.

GASZ is indispensable for gametogenesis in the silkworm, Bombyx mori.

The prominent role of the P-element induced wimpy testis (PIWI)-interacting RNA (piRNA) pathway in animals is to silence transposable elements and maintain genome stability, ensuring proper gametogenesis in gonads. GASZ (Germ cell protein with Ankyrin repeats, Sterile alpha motif, and leucine Zipper) is an evolutionarily conserved protein located on the outer mitochondrial membrane of germ cells and plays vital roles in the piRNA pathway and spermatogenesis in mammals. In the model insect Drosophila melanogaster, GASZ is essential for piRNA biogenesis and oogenesis, whereas its biological functions in non-drosophilid insects are still unknown. Here, we describe a comprehensive investigation of GASZ functions in the silkworm, Bombyx mori, a lepidopteran model insect, by using a binary transgenic CRISPR/Cas9 system. The BmGASZ mutation did not affect growth and development, but led to sterility in both males and females. Eupyrene sperm bundles of mutant males exhibited developmental defects, while the apyrene sperm bundles were normal, which were further confirmed through double copulation experiments with sex-lethal mutants, which males possess functional eupyrene sperm and abnormal apyrene sperm. In female mutant moths, ovarioles were severely degenerated and the eggs in ovarioles were deformed compared with that of wild type (WT). Further RNA-seq and RT-qPCR analysis revealed that amounts of piRNAs and transposon expression were dysregulated in gonads of mutants. In summary, this study has demonstrated vital roles of BmGASZ in gametogenesis through regulating the piRNA pathway in B. mori.