“…The fact that a gene is either testis-specific or highly testis-enriched is no indication that its deletion will impair male fertility. Some laboratories have recently generated several dozen testis-enriched knockout mouse lines and shown that all these genes are individually dispensable in terms of male fertility in mice ( Iwamori et al, 2011 ; Miyata et al, 2016 ; Khan et al, 2018 ; Lu et al, 2019 ; Chotiner et al, 2020 ; He et al, 2020 ; Khan et al, 2020 ; Jamin et al, 2021 ). The same is true for lncRNAs since their abundant expression during spermatogenesis has prompted other laboratories to produce knockout mouse models of testis-specific lncRNAs.…”
Spermatogenesis involves coordinated processes, including meiosis, to produce functional gametes. We previously reported Topaz1 as a germ cell-specific gene highly conserved in vertebrates. Topaz1 knockout males are sterile with testes that lack haploid germ cells because of meiotic arrest after prophase I. To better characterize Topaz1–/– testes, we used RNA-sequencing analyses at two different developmental stages (P16 and P18). The absence of TOPAZ1 disturbed the expression of genes involved in microtubule and/or cilium mobility, biological processes required for spermatogenesis. Moreover, a quarter of P18 dysregulated genes are long non-coding RNAs (lncRNAs), and three of them are testis-specific and located in spermatocytes, their expression starting between P11 and P15. The suppression of one of them, 4939463O16Rik, did not alter fertility although sperm parameters were disturbed and sperm concentration fell. The transcriptome of P18-4939463O16Rik–/– testes was altered and the molecular pathways affected included microtubule-based processes, the regulation of cilium movement and spermatogenesis. The absence of TOPAZ1 protein or 4930463O16Rik produced the same enrichment clusters in mutant testes despite a contrasted phenotype on male fertility. In conclusion, although Topaz1 is essential for the meiosis in male germ cells and regulate the expression of numerous lncRNAs, these studies have identified a Topaz1 regulated lncRNA (4930463O16Rik) that is key for both sperm production and motility.
“…The fact that a gene is either testis-specific or highly testis-enriched is no indication that its deletion will impair male fertility. Some laboratories have recently generated several dozen testis-enriched knockout mouse lines and shown that all these genes are individually dispensable in terms of male fertility in mice ( Iwamori et al, 2011 ; Miyata et al, 2016 ; Khan et al, 2018 ; Lu et al, 2019 ; Chotiner et al, 2020 ; He et al, 2020 ; Khan et al, 2020 ; Jamin et al, 2021 ). The same is true for lncRNAs since their abundant expression during spermatogenesis has prompted other laboratories to produce knockout mouse models of testis-specific lncRNAs.…”
Spermatogenesis involves coordinated processes, including meiosis, to produce functional gametes. We previously reported Topaz1 as a germ cell-specific gene highly conserved in vertebrates. Topaz1 knockout males are sterile with testes that lack haploid germ cells because of meiotic arrest after prophase I. To better characterize Topaz1–/– testes, we used RNA-sequencing analyses at two different developmental stages (P16 and P18). The absence of TOPAZ1 disturbed the expression of genes involved in microtubule and/or cilium mobility, biological processes required for spermatogenesis. Moreover, a quarter of P18 dysregulated genes are long non-coding RNAs (lncRNAs), and three of them are testis-specific and located in spermatocytes, their expression starting between P11 and P15. The suppression of one of them, 4939463O16Rik, did not alter fertility although sperm parameters were disturbed and sperm concentration fell. The transcriptome of P18-4939463O16Rik–/– testes was altered and the molecular pathways affected included microtubule-based processes, the regulation of cilium movement and spermatogenesis. The absence of TOPAZ1 protein or 4930463O16Rik produced the same enrichment clusters in mutant testes despite a contrasted phenotype on male fertility. In conclusion, although Topaz1 is essential for the meiosis in male germ cells and regulate the expression of numerous lncRNAs, these studies have identified a Topaz1 regulated lncRNA (4930463O16Rik) that is key for both sperm production and motility.
Spermatogenesis comprises a coordinated process, including meiosis, to produce fertile male gametes. Previous study reported that Topaz1 is a germ cell specific gene highly conserved in vertebrates. Topaz1 knockout male mice are sterile. The mutant testes lack haploid germ cells and meiosis arrests at the first-division prophase-metaphase transition. Here, in order to better characterize the testicular phenotype of Topaz1-/- mice, we used RNA-seq analyses at two different developmental stages. At postnatal days 16 (P16), 205 genes were differentially expressed genes (DEGs) in Topaz1-/- testes. They suggest stress conditions in mutant testes. At P18, the number of DEGs was increased 10-fold and 90% were down-regulated. The absence of Topaz1 seems to disturb the expression of genes involved in microtubule and/or cilium mobility, spermatogenesis and first meiotic division during the transition from prophase to metaphase. This is consistent with the Topaz1?/- testis phenotype where microtubule networks and centrosomes are disrupted. Moreover, a quarter of P18-DEGs are long non-coding RNAs (lncRNAs). Three of them, down-regulated at P16 and P18, were studied. They are testis-specific, located in spermatocytes and their expression starts between P11 and P15. We report here the effects of the suppression of one of these lncRNAs, 4939463O16Rik. The mouse fertility is not affected although the sperm parameters are disturbed. Transcriptome of P18-4939463O16Rik-/- testes is altered and the affected molecular pathways include microtubule-based process, regulation of cilium movement, spermatogenesis, male gamete differentiation. The absence of TOPAZ1 protein or of 4930463O16Rik lncRNA showed the same enrichment clusters in mutant testes despite a contrasted phenotype on the male fertility.
In conclusion, Topaz1 is an essential gene for male fertility in mice and seems to stabilize the expression of many lncRNAs. Its absence leads to meiotic arrest. Suppression of one lncRNA is dispensable for mouse fertility but is necessary during terminal differentiation of male gametes.
Background
As a group of membrane-anchored proteins, the proteins containing a disintegrin and metalloprotease domain (ADAMs) control many biological processes, especially for male fertility. Mouse Adam21 was previously found to be specifically expressed in the somatic cells and germ cells of testes, but its functional role during spermatogenesis and male reproductive processes is still unknown.
Methods
Adam21-null mice were created using the CRISPR/Cas9 system. Quantitative real-time PCR was used for analyzing of gene expression. Histological, cytological and immunofluorescence staining were performed to analyze the phenotypes of mouse testis and epididymis. Intracellular lipid droplets (LDs) were detected by Oil red O (ORO) staining and BODIPY staining. Fertility and sperm characteristics were also detected.
Results
Here, we successfully generated an Adam21 conventional knockout mouse model via CRISPR/Cas9 technology so that we can explore its potential role in male reproduction. We found that male mice lacking Adam21 have normal fertility without any detectable defects in spermatogenesis or sperm motility. Histological analysis of the seminiferous epithelium showed no obvious spermatogenesis difference between Adam21-null and wild-type mice. Cytological analysis revealed no detectable defects in meiotic progression, neither Sertoli cells nor Leydig cells displayed any defect compared with that of the control mice. All these results suggest that Adam21 might not be essential for male fertility in mice, and its potential function still needs further investigation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.