RESUMO
The structure of the sperm flagellar axoneme is highly conserved across species and serves the essential function of generating motility to facilitate the meeting of spermatozoa with the egg. During spermiogenesis, the axoneme elongates from the centrosome, and subsequently the centrosome docks onto the nuclear envelope to continue tail biogenesis. Mycbpap is expressed predominantly in mouse and human testes and conserved in Chlamydomonas as FAP147. A previous cryo-electron microscopy analysis has revealed the localization of FAP147 to the central apparatus of the axoneme. Here, we generated Mycbpap-knockout mice and demonstrated the essential role of Mycbpap in male fertility. Deletion of Mycbpap led to disrupted centrosome-nuclear envelope docking and abnormal flagellar biogenesis. Furthermore, we generated transgenic mice with tagged MYCBPAP, which restored the fertility of Mycbpap-knockout males. Interactome analyses of MYCBPAP using Mycbpap transgenic mice unveiled binding partners of MYCBPAP including central apparatus proteins, such as CFAP65 and CFAP70, which constitute the C2a projection, and centrosome-associated proteins, such as CCP110. These findings provide insights into a MYCBPAP-dependent regulation of the centrosome-nuclear envelope docking and sperm tail biogenesis.
Assuntos
Centrossomo , Camundongos Knockout , Membrana Nuclear , Cauda do Espermatozoide , Animais , Masculino , Membrana Nuclear/metabolismo , Centrossomo/metabolismo , Cauda do Espermatozoide/metabolismo , Cauda do Espermatozoide/ultraestrutura , Camundongos , Espermatogênese/genética , Camundongos Transgênicos , Fertilidade , Axonema/metabolismo , Axonema/ultraestrutura , Espermatozoides/metabolismo , Espermatozoides/ultraestruturaRESUMO
Sperm proteins undergo post-translational modifications during sperm transit through the epididymis to acquire fertilizing ability. We previously reported that the genomic region coding Pate family genes is key to the proteolytic processing of the sperm membrane protein ADAM3 and male fertility. This region contains nine Pate family genes (Pate5-13), and two protein-coding genes (Gm27235 and Gm5916), with a domain structure similar to Pate family genes. Therefore, in this study, we aimed to identify key factors by narrowing the genomic region. We generated three knockout (KO) mouse lines using CRISPR/Cas9: single KO mice of Pate10 expressed in the caput epididymis; deletion KO mice of six caput epididymis-enriched genes (Pate5-7, 13, Gm27235, and Gm5916) (Pate7-Gm5916 KO); and deletion KO mice of four genes expressed in the placenta and epididymis (Pate8, 9, 11, and 12) (Pate8-12 KO). We observed that the fertility of only Pate7-Gm5916 KO males was reduced, whereas the rest remained unaffected. Furthermore, when the caput epididymis-enriched genes, Pate8 and Pate10 remained in Pate7-Gm5916 KO mice were independently deleted, both KO males displayed more severe subfertility due to a decrease in mature ADAM3 and a defect in sperm migration to the oviduct. Thus, our data showed that multiple caput epididymis-enriched genes within the region coding Pate5-13 cooperatively function to ensure male fertility in mice.
Assuntos
Proteínas ADAM , Espermatozoides , Animais , Feminino , Masculino , Camundongos , Gravidez , Epididimo/metabolismo , Fertilidade/genética , Genômica , Camundongos Knockout , Sêmen , Espermatozoides/metabolismo , Proteínas ADAM/genética , Proteínas ADAM/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismoRESUMO
The mammalian spermatozoa produced in the testis require functional maturation in the epididymis for their full competence. Epididymal sperm maturation is regulated by lumicrine signalling pathways in which testis-derived secreted signals relocate to the epididymis lumen and promote functional differentiation. However, the detailed mechanisms of lumicrine regulation are unclear. Herein, we demonstrate that a small secreted protein, NELL2-interacting cofactor for lumicrine signalling (NICOL), plays a crucial role in lumicrine signalling in mice. NICOL is expressed in male reproductive organs, including the testis, and forms a complex with the testis-secreted protein NELL2, which is transported transluminally from the testis to the epididymis. Males lacking Nicol are sterile due to impaired NELL2-mediated lumicrine signalling, leading to defective epididymal differentiation and deficient sperm maturation but can be restored by NICOL expression in testicular germ cells. Our results demonstrate how lumicrine signalling regulates epididymal function for successful sperm maturation and male fertility.
Assuntos
Sêmen , Maturação do Esperma , Masculino , Camundongos , Animais , Testículo/metabolismo , Epididimo/metabolismo , Espermatozoides/metabolismo , Fertilidade , MamíferosRESUMO
Spermatozoa have a streamlined shape to swim through the oviduct to fertilize oocytes. To become svelte spermatozoa, spermatid cytoplasm must be eliminated in several steps including sperm release, which is part of spermiation. Although this process has been well observed, the molecular mechanisms that underlie it remain unclear. In male germ cells, there are membraneless organelles called nuage, which are observed by electron microscopy in various forms of dense material. Reticulated body (RB) and chromatoid body remnant (CR) are two types of nuage in spermatids, but the functions of both are unknown. Using CRISPR/Cas9 technology, we deleted the entire coding sequence of testis-specific serine kinase substrate (TSKS) in mice and demonstrate that TSKS is essential for male fertility through the formation of both RB and CR, prominent sites of TSKS localization. Due to the lack of TSKS-derived nuage (TDN), the cytoplasmic contents cannot be eliminated from spermatid cytoplasm in Tsks knockout mice, resulting in excess residual cytoplasm with an abundance of cytoplasmic materials and inducing an apoptotic response. In addition, ectopic expression of TSKS in cells results in formation of amorphous nuage-like structures; dephosphorylation of TSKS helps to induce nuage, while phosphorylation of TSKS blocks the formation. Our results indicate that TSKS and TDN are essential for spermiation and male fertility by eliminating cytoplasmic contents from the spermatid cytoplasm.
Assuntos
Proteínas do Citoesqueleto , Grânulos de Ribonucleoproteínas de Células Germinativas , Fosfoproteínas , Espermátides , Animais , Masculino , Camundongos , Citoplasma , Citosol , Camundongos Knockout , Sêmen , Proteínas do Citoesqueleto/genética , Fosfoproteínas/genéticaRESUMO
Sperm acrosomal membrane proteins, such as Izumo sperm-egg fusion 1 (IZUMO1) and sperm acrosome-associated 6 (SPACA6), play essential roles in mammalian gamete binding or fusion. How their biosynthesis is regulated during spermiogenesis has largely remained elusive. Here, we show that 1700029I15Rik knockout male mice are severely subfertile and their spermatozoa do not fuse with eggs. 1700029I15Rik is a type-II transmembrane protein expressed in early round spermatids but not in mature spermatozoa. It interacts with proteins involved in N-linked glycosylation, disulfide isomerization, and endoplasmic reticulum (ER)-Golgi trafficking, suggesting a potential role in nascent protein processing. The ablation of 1700029I15Rik destabilizes non-catalytic subunits of the oligosaccharyltransferase (OST) complex that are pivotal for N-glycosylation. The knockout testes exhibit normal expression of sperm plasma membrane proteins, but decreased abundance of multiple acrosomal membrane proteins involved in fertilization. The knockout sperm show upregulated chaperones related to ER-associated degradation (ERAD) and elevated protein ubiquitination; strikingly, SPACA6 becomes undetectable. Our results support for a specific, 1700029I15Rik-mediated pathway underpinning the biosynthesis of acrosomal membrane proteins during spermiogenesis.
Assuntos
Acrossomo , Proteínas de Membrana , Animais , Masculino , Camundongos , Acrossomo/metabolismo , Mamíferos/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos Knockout , Sêmen/metabolismo , Proteínas de Plasma Seminal/metabolismo , Interações Espermatozoide-Óvulo , Espermatozoides/metabolismo , Óvulo/metabolismoRESUMO
Spermatozoa need to undergo an exocytotic event called the acrosome reaction before fusing with eggs. Although calcium ion (Ca2+) is essential for the acrosome reaction, its molecular mechanism remains unknown. Ferlin is a single transmembrane protein with multiple Ca2+-binding C2 domains, and there are six ferlins, dysferlin (DYSF), otoferlin (OTOF), myoferlin (MYOF), fer-1-like 4 (FER1L4), FER1L5, and FER1L6, in mammals. Dysf, Otof, and Myof knockout mice have been generated, and each knockout mouse line exhibited membrane fusion disorders such as muscular dystrophy in Dysf, deafness in Otof, and abnormal myogenesis in Myof. Here, by generating mutant mice of Fer1l4, Fer1l5, and Fer1l6, we found that only Fer1l5 is required for male fertility. Fer1l5 mutant spermatozoa could migrate in the female reproductive tract and reach eggs, but no acrosome reaction took place. Even a Ca2+ ionophore cannot induce the acrosome reaction in Fer1l5 mutant spermatozoa. These results suggest that FER1L5 is the missing link between Ca2+ and the acrosome reaction.
Assuntos
Proteínas Musculares , Testículo , Masculino , Feminino , Animais , Camundongos , Membrana Celular/metabolismo , Proteínas Musculares/metabolismo , Testículo/metabolismo , Fusão de Membrana , Fertilidade , Espermatozoides/metabolismo , Mamíferos/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismoRESUMO
Spermatozoa released from the testis acquire fertilizing ability by translocating thorough the epididymis. Further, accessory gland secretions ejaculated into the female reproductive tract along with spermatozoa are also required to ensure male fecundity, such as the maintenance of proper sperm count and inhibition of premature sperm capacitation in the uterus. Here, we focus on a testis-enriched gene "Aldoart2", an epididymis-enriched gene "Serpina16", and seminal vesicle-enriched genes "Aoc1l3" and "Pate14" which were thought to be important for male fertility based on the previous studies. We independently deleted almost the entire protein-coding sequence of these genes in mice using CRISPR/Cas9. There were no overt defects in the histology and the sperm morphology and motility of any knockout (KO) mice. Further, Aoc1l3 and Pate14 KO males were able to form copulatory plugs. Finally, female mice that mated with these KO males delivered pups at a comparable level with the control males. Given our data, we demonstrated that the four genes predominantly expressed in the testis, epididymis, or seminal vesicle are independently dispensable for male fertility.
Assuntos
Fertilidade , Espermatozoides , Animais , Camundongos , Serpinas/genética , Testículo , Epididimo , Glândulas Seminais , Camundongos Knockout , Espermatozoides/fisiologia , Fertilização , Motilidade dos Espermatozoides , Frutose-Bifosfato Aldolase/genética , Amina Oxidase (contendo Cobre)/genética , Fertilidade/genéticaRESUMO
BACKGROUND: Lactate dehydrogenase C (LDHC) is specifically expressed in male germ cells and plays critical roles in glycolysis. Glycolysis is required to supply energy for sperm motility. Previous studies showed that Ldhc knock-out mice exhibit impaired sperm motility. OBJECTIVES: We established human LDHC knock-in (hLDHC KI) mice and examined whether hLDHC KI mice can be used to assess LDHC-targeting drugs. MATERIAL AND METHODS: HLDHC was knocked-in to the mouse Ldhc (mLdhc) allele using the CRISPR/Cas9 system. Mating tests, sperm motility examinations with a computer-assisted sperm analysis (CASA) system, and in vitro fertilization (IVF) were performed. Furthermore, the effect of an LDH inhibitor was analyzed with CASA and IVF. RESULTS: HLDHC was detected at the protein level in hLDHC KI spermatozoa. hLDHC KI mice exhibited comparable sperm motility and male fertility to wild-type (WT) mice. When we performed IVF using the LDH inhibitor more specific to hLDHC than mLDHC, fertilization rates were reduced in hLDHC KI mice but not in WT mice. DISCUSSION AND CONCLUSION: Our results reveal that hLDHC can rescue the absence of mLDHC. Differences in the effect of the LDH inhibitor between WT and hLDHC KI mice indicate that hLDHC KI mice can be a good model to assess hLDHC inhibitors for preclinical contraceptive studies.
Assuntos
Sêmen , Motilidade dos Espermatozoides , Humanos , Masculino , Camundongos , Animais , Espermatozoides/metabolismo , Anticoncepcionais , Camundongos KnockoutRESUMO
Meiosis is a hallmark event in germ cell development that accompanies sequential events executed by numerous molecules. Therefore, characterization of these factors is one of the best strategies to clarify the mechanism of meiosis. Here, we report tripartite motif-containing 41 (TRIM41), a ubiquitin ligase E3, as an essential factor for proper meiotic progression and fertility in male mice. Trim41 knockout (KO) spermatocytes exhibited synaptonemal complex protein 3 (SYCP3) overloading, especially on the X chromosome. Furthermore, mutant mice lacking the RING domain of TRIM41, required for the ubiquitin ligase E3 activity, phenocopied Trim41 KO mice. We then examined the behavior of mutant TRIM41 (ΔRING-TRIM41) and found that ΔRING-TRIM41 accumulated on the chromosome axes with overloaded SYCP3. This result suggested that TRIM41 exerts its function on the chromosome axes. Our study revealed that Trim41 is essential for preventing SYCP3 overloading, suggesting a TRIM41-mediated mechanism for regulating chromosome axis protein dynamics during male meiotic progression.
Assuntos
Proteínas Nucleares , Complexo Sinaptonêmico , Ubiquitina-Proteína Ligases/metabolismo , Animais , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Masculino , Meiose/genética , Camundongos , Camundongos Knockout , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Espermatócitos/metabolismo , Complexo Sinaptonêmico/genética , Complexo Sinaptonêmico/metabolismo , Ubiquitina-Proteína Ligases/genéticaRESUMO
The process of sperm-egg fusion is critical for successful fertilization, yet the underlying mechanisms that regulate these steps have remained unclear in vertebrates. Here, we show that both mouse and zebrafish DCST1 and DCST2 are necessary in sperm to fertilize the egg, similar to their orthologs SPE-42 and SPE-49 in C. elegans and Sneaky in D. melanogaster. Mouse Dcst1 and Dcst2 single knockout (KO) sperm are able to undergo the acrosome reaction and show normal relocalization of IZUMO1, an essential factor for sperm-egg fusion, to the equatorial segment. While both single KO sperm can bind to the oolemma, they show the fusion defect, resulting that Dcst1 KO males become almost sterile and Dcst2 KO males become sterile. Similar to mice, zebrafish dcst1 KO males are subfertile and dcst2 and dcst1/2 double KO males are sterile. Zebrafish dcst1/2 KO sperm are motile and can approach the egg, but are defective in binding to the oolemma. Furthermore, we find that DCST1 and DCST2 interact with each other and are interdependent. These data demonstrate that DCST1/2 are essential for male fertility in two vertebrate species, highlighting their crucial role as conserved factors in fertilization.
Assuntos
Interações Espermatozoide-Óvulo , Peixe-Zebra , Animais , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Espermatozoides/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/metabolismoRESUMO
The acrosome is a cap-shaped, Golgi-derived membranous organelle that is located over the anterior of the sperm nucleus and highly conserved throughout evolution. Although morphological changes during acrosome biogenesis in spermatogenesis have been well described, the molecular mechanism underlying this process is still largely unknown. Family with sequence similarity 71, member F1 and F2 (FAM71F1 and FAM71F2) are testis-enriched proteins that contain a RAB2B-binding domain, a small GTPase involved in vesicle transport and membrane trafficking. Here, by generating mutant mice for each gene, we found that Fam71f1 is essential for male fertility. In Fam71f1-mutant mice, the acrosome was abnormally expanded at the round spermatid stage, likely because of enhanced vesicle trafficking. Mass spectrometry analysis after immunoprecipitation indicated that, in testes, FAM71F1 binds not only RAB2B, but also RAB2A. Further study suggested that FAM71F1 binds to the GTP-bound active form of RAB2A/B, but not the inactive form. These results indicate that a complex of FAM71F1 and active RAB2A/B suppresses excessive vesicle trafficking during acrosome formation.
Assuntos
Acrossomo/metabolismo , Fertilidade/fisiologia , Proteínas Nucleares/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Proteína rab2 de Ligação ao GTP/metabolismo , Acrossomo/patologia , Animais , Genética , Complexo de Golgi/metabolismo , Infertilidade Masculina , Masculino , Camundongos , Camundongos Transgênicos , Proteínas Nucleares/genética , Ligação Proteica , Cabeça do Espermatozoide/metabolismo , Espermatogênese , Teratozoospermia/metabolismo , Testículo/metabolismoRESUMO
Cilia and flagella are ancient structures that achieve controlled motor functions through the coordinated interaction based on microtubules and some attached projections. Radial spokes (RSs) facilitate the beating motion of these organelles by mediating signal transduction between dyneins and a central pair (CP) of singlet microtubules. RS complex isolation from Chlamydomonas axonemes enabled the detection of 23 radial spoke proteins (RSP1-RSP23), although the roles of some radial spoke proteins remain unknown. Recently, RSP15 has been reported to be bound to the stalk of RS2, but its homolog in mammals has not been identified. Herein, we show that Lrrc23 is an evolutionarily conserved testis-enriched gene encoding an RSP15 homolog in mice. We found that LRRC23 localizes to the RS complex within murine sperm flagella and interacts with RSPH3A and RSPH3B. The knockout of Lrrc23 resulted in male infertility due to RS disorganization and impaired motility in murine spermatozoa, whereas the ciliary beating was not significantly affected. These data indicate that LRRC23 is a key regulator that underpins the integrity of the RS complex within the flagella of mammalian spermatozoa, whereas it is dispensable in cilia. This article has an associated First Person interview with the first author of the paper.
Assuntos
Axonema , Proteínas do Citoesqueleto/metabolismo , Motilidade dos Espermatozoides , Animais , Axonema/metabolismo , Cílios/metabolismo , Proteínas do Citoesqueleto/genética , Dineínas/metabolismo , Fertilidade/genética , Flagelos/metabolismo , Masculino , Camundongos , Motilidade dos Espermatozoides/genéticaRESUMO
The clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 system is a research hotspot in gene therapy. However, the widely used Streptococcus pyogenes Cas9 (WT-SpCas9) requires an NGG protospacer adjacent motif (PAM) for target recognition, thereby restricting targetable disease mutations. To address this issue, we recently reported an engineered SpCas9 nuclease variant (SpCas9-NG) recognizing NGN PAMs. Here, as a feasibility study, we report SpCas9-NG-mediated repair of the abnormally expanded CAG repeat tract in Huntington's disease (HD). By targeting the boundary of CAG repeats with SpCas9-NG, we precisely contracted the repeat tracts in HD-mouse-derived embryonic stem (ES) cells. Further, we confirmed the recovery of phenotypic abnormalities in differentiated neurons and animals produced from repaired ES cells. Our study shows that SpCas9-NG can be a powerful tool for repairing abnormally expanded CAG repeats as well as other disease mutations that are difficult to access with WT-SpCas9.
Assuntos
Proteína 9 Associada à CRISPR/fisiologia , Edição de Genes , Doença de Huntington/genética , Repetições de Trinucleotídeos , Animais , Linhagem Celular , Modelos Animais de Doenças , Células-Tronco Embrionárias/citologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICRAssuntos
Antígenos de Superfície/genética , Comunicação Celular/genética , Tubas Uterinas/metabolismo , Fertilização/genética , Reprodução/genética , Espermatozoides/metabolismo , Animais , Copulação/fisiologia , Tubas Uterinas/anatomia & histologia , Feminino , Proteínas Ligadas por GPI/deficiência , Proteínas Ligadas por GPI/genética , Regulação da Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Tamanho da Ninhada de Vivíparos , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/metabolismo , Transdução de Sinais , Contagem de Espermatozoides , Motilidade dos Espermatozoides/genética , Útero/anatomia & histologia , Útero/metabolismoRESUMO
Post-meiotic spermatids become spermatozoa through developmental stages during spermiogenesis. Isolation of spermatid fractions is required to examine the change of protein expression during spermiogenesis. Here, we present a simple method to isolate spermatid fractions from mouse testes using unit gravity sedimentation in a BSA density gradient. Isolation of spermatid fractions can be used to analyze changes of transcript or protein during spermiogenesis. For complete details on the use and execution of this protocol, please refer to Kim et al. (2020).
Assuntos
Separação Celular , Espermátides/citologia , Testículo/citologia , Animais , Masculino , Camundongos , Espermátides/metabolismo , Espermatogênese , Testículo/metabolismoRESUMO
Fertilization occurs as the culmination of multi-step complex processes. First, mammalian spermatozoa undergo the acrosome reaction to become fusion-competent. Then, the acrosome-reacted spermatozoa penetrate the zona pellucida and adhere to and finally fuse with the egg plasma membrane. IZUMO1 is the first sperm protein proven to be essential for sperm-egg fusion in mammals, as Izumo1 knockout mouse spermatozoa adhere to but fail to fuse with the oolemma. However, the IZUMO1 function in other species remains largely unknown. Here, we generated Izumo1 knockout rats by CRISPR/Cas9 and found the male rats were infertile. Unlike in mice, Izumo1 knockout rat spermatozoa failed to bind to the oolemma. Further investigation revealed that the acrosome-intact sperm binding conceals a decreased number of the acrosome-reacted sperm bound to the oolemma in Izumo1 knockout mice. Of note, we could not see any apparent defects in the binding of the acrosome-reacted sperm to the oolemma in the mice lacking recently found fusion-indispensable genes, Fimp, Sof1, Spaca6, or Tmem95. Collectively, our data suggest that IZUMO1 is required for the sperm-oolemma binding prior to fusion at least in rat.
RESUMO
OBJECTIVE: NFκB is the key modulator in inflammatory disorders. However, the key regulators that activate, fine-tune or shut off NFκB activity in inflammatory conditions are poorly understood. In this study, we aim to investigate the roles that NFκB-specific long non-coding RNAs (lncRNAs) play in regulating inflammatory networks. DESIGN: Using the first genetic-screen to identify NFκB-specific lncRNAs, we performed RNA-seq from the p65-/- and Ikkß-/- mouse embryonic fibroblasts and report the identification of an evolutionary conserved lncRNA designated mNAIL (mice) or hNAIL (human). hNAIL is upregulated in human inflammatory disorders, including UC. We generated mNAILΔNFκB mice, wherein deletion of two NFκB sites in the proximal promoter of mNAIL abolishes its induction, to study its function in colitis. RESULTS: NAIL regulates inflammation via sequestering and inactivating Wip1, a known negative regulator of proinflammatory p38 kinase and NFκB subunit p65. Wip1 inactivation leads to coordinated activation of p38 and covalent modifications of NFκB, essential for its genome-wide occupancy on specific targets. NAIL enables an orchestrated response for p38 and NFκB coactivation that leads to differentiation of precursor cells into immature myeloid cells in bone marrow, recruitment of macrophages to inflamed area and expression of inflammatory genes in colitis. CONCLUSION: NAIL directly regulates initiation and progression of colitis and its expression is highly correlated with NFκB activity which makes it a perfect candidate to serve as a biomarker and a therapeutic target for IBD and other inflammation-associated diseases.
Assuntos
Colite/genética , Colite/metabolismo , RNA Longo não Codificante/metabolismo , Fator de Transcrição RelA/metabolismo , Animais , Biomarcadores/metabolismo , Progressão da Doença , Fibroblastos/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases , Camundongos , Proteína Fosfatase 2C/metabolismoRESUMO
Sperm malformation is a direct factor for male infertility. Multiple morphological abnormalities of the flagella (MMAF), a severe form of asthenoteratozoospermia, are characterized by immotile spermatozoa with malformed and/or absent flagella in the ejaculate. Previous studies indicated genetic heterogeneity in MMAF. To further define genetic factors underlying MMAF, we performed whole-exome sequencing in a cohort of 90 Chinese MMAF-affected men. Two cases (2.2%) were identified as carrying bi-allelic missense DNAH8 variants, variants which were either absent or rare in the control human population and were predicted to be deleterious by multiple bioinformatic tools. Re-analysis of exome data from a second cohort of 167 MMAF-affected men from France, Iran, and North Africa permitted the identification of an additional male carrying a DNAH8 homozygous frameshift variant. DNAH8 encodes a dynein axonemal heavy-chain component that is expressed preferentially in the testis. Hematoxylin-eosin staining and electron microscopy analyses of the spermatozoa from men harboring bi-allelic DNAH8 variants showed a highly aberrant morphology and ultrastructure of the sperm flagella. Immunofluorescence assays performed on the spermatozoa from men harboring bi-allelic DNAH8 variants revealed the absent or markedly reduced staining of DNAH8 and its associated protein DNAH17. Dnah8-knockout male mice also presented typical MMAF phenotypes and sterility. Interestingly, intracytoplasmic sperm injections using the spermatozoa from Dnah8-knockout male mice resulted in good pregnancy outcomes. Collectively, our experimental observations from humans and mice demonstrate that DNAH8 is essential for sperm flagellar formation and that bi-allelic deleterious DNAH8 variants lead to male infertility with MMAF.
Assuntos
Anormalidades Múltiplas/genética , Dineínas do Axonema/genética , Flagelos/genética , Variação Genética/genética , Infertilidade Masculina/genética , Cauda do Espermatozoide/patologia , Alelos , Animais , Estudos de Coortes , Exoma/genética , Feminino , Homozigoto , Humanos , Masculino , Camundongos , Camundongos Knockout , Espermatozoides/anormalidades , Testículo/anormalidades , Sequenciamento do Exoma/métodosRESUMO
Spermatogenesis is a complex process of sperm generation, including mitosis, meiosis, and spermiogenesis. During spermiogenesis, histones in post-meiotic spermatids are removed from chromatin and replaced by protamines. Although histone-to-protamine exchange is important for sperm nuclear condensation, the underlying regulatory mechanism is still poorly understood. Here, we identify PHD finger protein 7 (PHF7) as an E3 ubiquitin ligase for histone H3K14 in post-meiotic spermatids. Generation of Phf7-deficient mice and Phf7 C160A knockin mice with impaired E3 ubiquitin ligase activity reveals defects in histone-to-protamine exchange caused by dysregulation of histone removal factor Bromodomain, testis-specific (BRDT) in early condensing spermatids. Surprisingly, E3 ubiquitin ligase activity of PHF7 on histone ubiquitination leads to stabilization of BRDT by attenuating ubiquitination of BRDT. Collectively, our findings identify PHF7 as a critical factor for sperm chromatin condensation and contribute to mechanistic understanding of fundamental phenomenon of histone-to-protamine exchange and potential for drug development for the male reproduction system.
Assuntos
Espermatogênese/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Acetilação , Animais , Núcleo Celular/metabolismo , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina , Técnicas de Introdução de Genes/métodos , Células HEK293 , Histonas/metabolismo , Humanos , Masculino , Meiose , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Nucleares/metabolismo , Proteínas Nucleares/fisiologia , Protaminas/metabolismo , Espermátides/metabolismo , Espermatogênese/fisiologia , Espermatozoides/metabolismo , Testículo/metabolismo , UbiquitinaçãoRESUMO
Spermatozoa are produced in the testis but gain their fertilizing ability during epididymal migration. This necessary step in sperm maturation includes posttranslational modification of sperm membrane proteins that includes protein processing by proteases. However, the molecular mechanism underpinning this epididymal sperm maturation remains unknown. In this study, we focused on transmembrane serine protease 12 (Tmprss12). Based on multi-tissue expression analysis by PCR, Tmprss12 was specifically expressed in the testis, and its expression started on day 10 postpartum, corresponding to the stage of zygotene spermatocytes. TMPRSS12 was detected in the acrosomal region of spermatozoa by immunostaining. To reveal the physiological function of TMPRSS12, we generated two knockout (KO) mouse lines using the CRISPR/Cas9 system. Both indel and large deletion lines were male sterile showing that TMPRSS12 is essential for male fertility. Although KO males exhibited normal spermatogenesis and sperm morphology, ejaculated spermatozoa failed to migrate from the uterus to the oviduct. Further analysis revealed that a disintegrin and metalloprotease 3 (ADAM3), an essential protein on the sperm membrane surface that is required for sperm migration, was disrupted in KO spermatozoa. Moreover, we found that KO spermatozoa showed reduced sperm motility via computer-assisted sperm analysis, resulting in a low fertilization rate in vitro. Taken together, these data indicate that TMPRSS12 has dual functions in regulating sperm motility and ADAM3-related sperm migration to the oviduct. Because Tmprss12 is conserved among mammals, including humans, our results may explain some genetic cases of idiopathic male infertility, and TMPRSS12 and its downstream cascade may be novel targets for contraception.