Infertility with impaired zona pellucida adhesion of spermatozoa from mice lacking TauCstF-64

Loss of Cep135 causes oligoasthenoteratozoospermia and male infertility in mice

Centrosomal proteins (Cep), as crucial scaffolding molecules, play a pivotal role in the biogenesis of centrioles and the regulation of the cell cycle. To date, mutation in Cep135 has been reported to be closely associated with multiple morphological abnormalities of the flagella (MMAF) in humans. However, the specific mechanism of Cep135 in spermatogenesis and its detailed role in male infertility remains largely unexplored. In this study, we present compelling evidence that Cep135 functions as a pathogenic gene responsible for oligoasthenoteratozoospermia (OAT) and male infertility in mice. By selectively deleting Cep135 in premeiotic germ cells using Stra8-Cre mice crossed with Cep135flox/flox mice, we observed that Cep135 knockdown produced abnormal sperm morphology, germ cell apoptosis and consequentlybecame complete infertility, but did not impact premeiosis. Scanning and transmission electron microscopy revealed defects in acrosome, flagellum, and head-to-tail connections during spermatogenesis. Proteomic analysis further indicated that CEP135 deletion led to a significant reduction in proteins mainly associated with acrosome formation, sperm heads, sperm flagellum and microtubule assembly. Additionally, CEP135 interacts with spermatogenic proteins SPATA6 and AKAP3, regulating their expression and stability. Deficiency in CEP135 or its interacting proteins resulted in ciliary shortening. In conclusion, our study profoundly unveils the central role of Cep135 in spermatogenesis and male fertility. This discovery not only deepens our comprehension of spermatogenesis but also furnishes a solid theoretical foundation and experimental evidence that can guide the formulation of therapeutic and preventive strategies for male infertility.

Cervical mucus in linked human Cervix and Vagina Chips modulates vaginal dysbiosis

This study explores the protective role of cervicovaginal mucus in maintaining vaginal health, particularly in relation to bacterial vaginosis (BV), using organ chip technology. By integrating human Cervix and Vagina Chips, we demonstrated that cervical mucus significantly reduces inflammation and epithelial damage caused by a dysbiotic microbiome commonly associated with BV. Proteomic analysis of the Vagina Chip, following exposure to mucus from the Cervix Chip, revealed differentially abundant proteins, suggesting potential biomarkers and therapeutic targets for BV management. Our findings highlight the essential function of cervical mucus in preserving vaginal health and underscore the value of organ chip models for studying complex interactions within the female reproductive tract. This research provides new insights into the mechanisms underlying vaginal dysbiosis and opens avenues for developing targeted therapies and diagnostic tools to enhance women's reproductive health.

The role of CSTF2 in cancer: from technology to clinical application

A protein called cleavage-stimulating factor subunit 2 (CSTF2, additionally called CSTF-64) binds RNA and is needed for the cleavage and polyadenylation of mRNA. CSTF2 is an important component subunit of the cleavage stimulating factor (CSTF), which is located on the X chromosome and encodes 557 amino acids. There is compelling evidence linking elevated CSTF2 expression to the pathological advancement of cancer and on its impact on the clinical aspects of the disease. The progression of cancers, including hepatocellular carcinoma, melanoma, prostate cancer, breast cancer, and pancreatic cancer, is correlated with the upregulation of CSTF2 expression. This review provides a fresh perspective on the investigation of the associations between CSTF2 and various malignancies and highlights current studies on the regulation of CSTF2. In particular, the mechanism of action and potential clinical applications of CSTF2 in cancer suggest that CSTF2 can serve as a new biomarker and individualized treatment target for a variety of cancer types.

Novel mutations of TEX11 are associated with non-obstructive azoospermia

Non-obstructive azoospermia (NOA) affects 10% of infertile men worldwide, and genetic studies revealed that there are plenty of monogenic mutations that responsible for a part of idiopathic NOA cases. Testis-expressed gene 11 (TEX11) is an X-linked meiosis-specific gene, many pathogenic variants in TEX11 have been detected in NOA patients, and the deficiency of this gene can cause abnormal meiotic recombination and chromosomal synapsis. However, many NOA-affected cases caused by TEX11 mutation remain largely unknown. This study reported three novel TEX11 mutations (exon 5, c.313C>T: p.R105*), (exon 7, c.427A>C: p.K143Q) and (exon 29, c.2575G>A: p.G859R). Mutations were screened using whole-exome sequencing (WES) and further verified by amplifying and sequencing the specific exon. Histological analysis of testicular biopsy specimens revealed a thicker basement membrane of the seminiferous tubules and poorly developed spermatocytes, and no post-meiotic round spermatids or mature spermatozoa were observed in the seminiferous tubules of patients with TEX11 mutation.

Conclusion

This study presents three novel variants of TEX11 as potential infertility alleles that have not been previously reported. It expanded the variant spectrum of patients with NOA, which also emphasizes the necessity of this gene screening for the clinical auxiliary diagnosis of patients with azoospermia.

Cleavage Stimulation Factor Subunit 2: Function Across Cancers and Potential Target for Chemotherapeutic Drugs

The cleavage stimulation factor subunit complex is involved in the cleavage and polyadenylation of 3′-end pre-mRNAs that regulate mRNA formation and processing. However, cleavage stimulation factor subunit 2 (CSTF2) was found to play a more critical regulatory role across cancers. General cancer data sets from The Cancer Genome Atlas and Genotype-Tissue Expression project were thus downloaded for differential analysis, and the possible functions and mechanisms of CSTF2 in general cancer were analyzed using the Compartments database, cBioPortal database, Tumor Immune Single-cell Hub database, and Comparative Toxigenomics database using gene set enrichment analysis and R software. The results showed that CSTF2 could affect DNA repair and methylation in tumor cells. In addition, CSTF2 was associated with multiple tumor immune infiltrates in a wide range of cancers, and its high expression was associated with multiple immune checkpoints; therefore, it could serve as a potential target for many drug molecules. We also proved that CSTF2 promotes oral cell proliferation and migration. The high diagnostic efficacy of CSTF2 suggested that this gene may act as a new biomarker and personalized therapeutic target for a variety of tumors.

The Dispensable Roles of X-Linked Ubl4a and Its Autosomal Counterpart Ubl4b in Spermatogenesis Represent a New Evolutionary Type of X-Derived Retrogenes

X-derived retrogenes contribute to genetic diversity in evolution and are usually specifically expressed in testis and perform important functions during spermatogenesis. Ubl4b is an autosomal retrogene with testis-specific expression derived from Ubl4a, an X-linked housekeeping gene. In the current study, we performed phylogenetic analysis and revealed that Ubl4a and Ubl4b are subject to purifying selection and may have conserved functions in evolution. Ubl4b was knocked out in mice using CRISPR/Cas9 genome editing technology and interestingly, we found no alterations in reproductive parameters of Ubl4b^-/- male mice. To get insights into whether Ubl4a could compensate the absence of Ubl4b in vivo, we further obtained Ubl4a^-/Y; Ubl4b^-/- mice that lack both Ubl4a and Ubl4b, and the double knockout (dKO) mice also displayed normal spermatogenesis, showing that Ubl4a and Ubl4b are both dispensable for spermatogenesis. Thus, through the in vivo study of UBL4A and UBL4B, we provided a direct evidence for the first time that some X chromosome-derived autosomal retrogenes can be unfunctional in spermatogenesis, which represents an additional evolutionary type of X-derived retrogenes.

First Infertile Case with CSTF2TGene Mutation

Male infertility is multifactorial and presents with heterogeneous phenotypic features. Genetic factors are responsible for up to 15% of the male infertility cases. Loss of the Cstf2t gene in male mice results in infertility. No disease-associated mutations have been described for this gene in infertile men. Here, we report a patient diagnosed with infertility in whom a homozygous nonsense mutation in the CSTF2T gene was detected by clinical exome sequencing. This case is the first description of an infertile patient who has a homozygous CSTF2T mutation.

A homozygous RPL10L missense mutation associated with male factor infertility and severe oligozoospermia

OBJECTIVE

To identify the genetic cause of male factor infertility characterized by severe oligozoospermia.

DESIGN

Genetic studies.

SETTING

Medical university.

PATIENT(S)

Two infertile brothers with severe oligozoospermia in a consanguineous Han Chinese family, 414 additional patients with oligo-/azoospermia, and 223 fertile (control) subjects.

INVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Genetic analyses using whole-exome and Sanger sequencing were performed for two brothers with severe oligozoospermia. The effects of an identified candidate causative mutation were investigated in silico and in vitro. Whole-exome sequencing screening for the candidate mutation was conducted in 414 patients with oligo-/azoospermia and 223 fertile subjects.

RESULT(S)

A homozygous missense variant (NM_080746:c.A257C: p.H86P) in RPL10L was identified in the two affected brothers and shown to cosegregate with the severe oligozoospermia phenotype. The mutation was absent in public databases, including the 1000 Genomes Project and the Exome Aggregation Consortium. All queried databases predicted the mutation to be damaging, consistent with the fact that it decreased protein levels in vitro. Subsequent mutation screening identified three additional heterozygous RPL10L mutations in three of 414 subjects with oligo-/azoospermia, but no RPL10L mutations among 223 fertile subjects.

CONCLUSION(S)

Our findings implicate RPL10L as a novel candidate gene in the pathogenesis of human male factor infertility and severe oligozoospermia.

Copy Number Variation Mapping and Genomic Variation of Autochthonous and Commercial Turkey Populations

This study aims at investigating genomic diversity of several turkey populations using Copy Number Variants (CNVs). A total of 115 individuals from six Italian breeds (Colle Euganei, Bronzato Comune Italiano, Parma e Piacenza, Brianzolo, Nero d'Italia, and Ermellinato di Rovigo), seven Narragansett, 38 commercial hybrids, and 30 Mexican turkeys, were genotyped with the Affymetrix 600K single nucleotide polymorphism (SNP) turkey array. The CNV calling was performed with the Hidden Markov Model of PennCNV software and with the Copy Number Analysis Module of SVS 8.4 by Golden Helix^®. CNV were summarized into CNV regions (CNVRs) at population level using BEDTools. Variability among populations has been addressed by hierarchical clustering (pvclust R package) and by principal component analysis (PCA). A total of 2,987 CNVs were identified covering 4.65% of the autosomes of the Turkey_5.0/melGal5 assembly. The CNVRs identified in at least two individuals were 362-189 gains, 116 losses, and 57 complexes. Among these regions the 51% contain annotated genes. This study is the first CNV mapping of turkey population using 600K chip. CNVs clustered the individuals according to population and their geographical origin. CNVs are known to be indicators also of adaptation, as some researches in different species are suggesting.

Cstf2t Regulates expression of histones and histone-like proteins in male germ cells

Formation of the 3' ends of mature mRNAs requires recognition of the correct site within the last exon, cleavage of the nascent pre-mRNA, and, for most mRNAs, addition of a poly(A) tail. Several factors are involved in recognition of the correct 3'-end site. The cleavage stimulation factor (CstF) has three subunits, CstF-50 (gene symbol Cstf1), CstF-64 (Cstf2), and CstF-77 (Cstf3). Of these, CstF-64 is the RNA-binding subunit that interacts with the pre-mRNA downstream of the cleavage site. In male germ cells where CstF-64 is not expressed, a paralog, τCstF-64 (gene symbol Cstf2t) assumes its functions. Accordingly, Cstf2t knockout (Cstf2t^-/- ) mice exhibit male infertility due to defective development of spermatocytes and spermatids. To discover differentially expressed genes responsive to τCstF-64, we performed RNA-Seq in seminiferous tubules from wild-type and Cstf2t^-/- mice, and found that several histone and histone-like mRNAs were reduced in Cstf2t^-/- mice. We further observed delayed accumulation of the testis-specific histone, H1fnt (formerly, H1t2 or Hanp1) in Cstf2t^-/- mice. High-throughput sequence analysis of polyadenylation sites (A-seq) indicated reduced use of polyadenylation sites within a cluster downstream of H1fnt in knockout mice. However, high-throughput sequencing of RNA isolated by cross-linking immunoprecipitation (HITS-CLIP) was not consistent with a direct role of τCstF-64 in polyadenylation of H1fnt. These findings together suggest that the τCstF-64 may control other reproductive functions that are not directly linked to the formation of 3' ends of mature polyadenylated mRNAs during male germ cell formation.

The Cstf2t Polyadenylation Gene Plays a Sex-Specific Role in Learning Behaviors in Mice

Polyadenylation is an essential mechanism for the processing of mRNA 3′ ends. CstF-64 (the 64,000 M_r subunit of the cleavage stimulation factor; gene symbol Cstf2) is an RNA-binding protein that regulates mRNA polyadenylation site usage. We discovered a paralogous form of CstF-64 called τCstF-64 (Cstf2t). The Cstf2t gene is conserved in all eutherian mammals including mice and humans, but the τCstF-64 protein is expressed only in a subset of mammalian tissues, mostly testis and brain. Male mice that lack Cstf2t (Cstf2t^-/- mice) experience disruption of spermatogenesis and are infertile, although female fertility is unaffected. However, a role for τCstF-64 in the brain has not yet been determined. Given the importance of RNA polyadenylation and splicing in neuronal gene expression, we chose to test the hypothesis that τCstF-64 is important for brain function. Male and female 185-day old wild type and Cstf2t^-/- mice were examined for motor function, general activity, learning, and memory using rotarod, open field activity, 8-arm radial arm maze, and Morris water maze tasks. Male wild type and Cstf2t^-/- mice did not show differences in learning and memory. However, female Cstf2t^-/- mice showed significantly better retention of learned maze tasks than did female wild type mice. These results suggest that τCstf-64 is important in memory function in female mice. Interestingly, male Cstf2t^-/- mice displayed less thigmotactic behavior than did wild type mice, suggesting that Cstf2t may play a role in anxiety in males. Taken together, our studies highlight the importance of mRNA processing in cognition and behavior as well as their established functions in reproduction.

Roles of RNA-binding Proteins and Post-transcriptional Regulation in Driving Male Germ Cell Development in the Mouse

Tissue development and homeostasis are dependent on highly regulated gene expression programs in which cell-specific combinations of regulatory factors determine which genes are expressed and the post-transcriptional fate of the resulting RNA transcripts. Post-transcriptional regulation of gene expression by RNA-binding proteins has critical roles in tissue development-allowing individual genes to generate multiple RNA and protein products, and the timing, location, and abundance of protein synthesis to be finely controlled. Extensive post-transcriptional regulation occurs during mammalian gametogenesis, including high levels of alternative mRNA expression, stage-specific expression of mRNA variants, broad translational repression, and stage-specific activation of mRNA translation. In this chapter, an overview of the roles of RNA-binding proteins and the importance of post-transcriptional regulation in male germ cell development in the mouse is presented.

TauCstF-64 Mediates Correct mRNA Polyadenylation and Splicing of Activator and Repressor Isoforms of the Cyclic AMP-Responsive Element Modulator (CREM) in Mouse Testis

Spermatogenesis is coordinated by the spatial and temporal expression of many transcriptional and posttranscriptional factors. The cyclic AMP-responsive element modulator (CREM) gene encodes both activator and repressor isoforms that act as transcription factors to regulate spermiogenesis. We found that the testis-expressed paralog of CstF-64, tauCstF-64 (gene symbol Cstf2t), is involved in a polyadenylation site choice switch of Crem mRNA and leads to an overall decrease of the Crem mRNAs that are generated from internal promoters in Cstf2t(-/-) mice. More surprisingly, loss of tauCstF-64 also leads to alternative splicing of Crem exon 4, which contains an important activation domain. Thus, testis-specific CREMtau2 isoform protein levels are reduced in Cstf2t(-/-) mice. Consequently, expression of 15 CREM-regulated genes is decreased in testes of Cstf2t(-/-) mice at 25 days postpartum. These effects might further contribute to the infertility phenotype of these animals. This demonstrates that tauCstF-64 is an important stage-specific regulator of Crem mRNA processing that modulates the spatial and temporal expression of downstream stage-specific genes necessary for the proper development of sperm in mice.

CstF-64 is necessary for endoderm differentiation resulting in cardiomyocyte defects

Although adult cardiomyocytes have the capacity for cellular regeneration, they are unable to fully repair severely injured hearts. The use of embryonic stem cell (ESC)-derived cardiomyocytes as transplantable heart muscle cells has been proposed as a solution, but is limited by the lack of understanding of the developmental pathways leading to specification of cardiac progenitors. Identification of these pathways will enhance the ability to differentiate cardiomyocytes into a clinical source of transplantable cells. Here, we show that the mRNA 3' end processing protein, CstF-64, is essential for cardiomyocyte differentiation in mouse ESCs. Loss of CstF-64 in mouse ESCs results in loss of differentiation potential toward the endodermal lineage. However, CstF-64 knockout (Cstf2(E6)) cells were able to differentiate into neuronal progenitors, demonstrating that some differentiation pathways were still intact. Markers for mesodermal differentiation were also present, although Cstf2(E6) cells were defective in forming beating cardiomyocytes and expressing cardiac specific markers. Since the extraembryonic endoderm is needed for cardiomyocyte differentiation and endodermal markers were decreased, we hypothesized that endodermal factors were required for efficient cardiomyocyte formation in the Cstf2(E6) cells. Using conditioned medium from the extraembryonic endodermal (XEN) stem cell line we were able to restore cardiomyocyte differentiation in Cstf2(E6) cells, suggesting that CstF-64 has a role in regulating endoderm differentiation that is necessary for cardiac specification and that extraembryonic endoderm signaling is essential for cardiomyocyte development.

CstF-64 supports pluripotency and regulates cell cycle progression in embryonic stem cells through histone 3' end processing

Embryonic stem cells (ESCs) exhibit a unique cell cycle with a shortened G1 phase that supports their pluripotency, while apparently buffering them against pro-differentiation stimuli. In ESCs, expression of replication-dependent histones is a main component of this abbreviated G1 phase, although the details of this mechanism are not well understood. Similarly, the role of 3' end processing in regulation of ESC pluripotency and cell cycle is poorly understood. To better understand these processes, we examined mouse ESCs that lack the 3' end-processing factor CstF-64. These ESCs display slower growth, loss of pluripotency and a lengthened G1 phase, correlating with increased polyadenylation of histone mRNAs. Interestingly, these ESCs also express the τCstF-64 paralog of CstF-64. However, τCstF-64 only partially compensates for lost CstF-64 function, despite being recruited to the histone mRNA 3' end-processing complex. Reduction of τCstF-64 in CstF-64-deficient ESCs results in even greater levels of histone mRNA polyadenylation, suggesting that both CstF-64 and τCstF-64 function to inhibit polyadenylation of histone mRNAs. These results suggest that CstF-64 plays a key role in modulating the cell cycle in ESCs while simultaneously controlling histone mRNA 3' end processing.

Safety, efficacy and efficiency of laser-assisted IVF in subfertile mutant mouse strains

In the present report we studied the safety, efficacy and efficiency of using an infrared laser to facilitate IVF by assessing fertilization, development and birth rates after laser-zona drilling (LZD) in 30 subfertile genetically modified (GM) mouse lines. We determined that LZD increased the fertilization rate four to ten times that of regular IVF, thus facilitating the derivation of 26 of 30 (86.7%) GM mouse lines. Cryopreserved two-cell stage embryos derived by LZD-assisted IVF were recovered and developed to blastocysts in vitro at the same rate as frozen-thawed embryos derived by regular IVF. Surprisingly after surgical transfer to pseudopregnant recipients the birth rate of embryos derived by LZD-assisted IVF was significantly lower than that of embryos derived by regular IVF. However this result could be completely mitigated by the addition of 0.25 M sucrose to the culture medium during LZD which caused the oocyte to shrink in volume relative to the perivitelline space. By increasing the distance from the laser target site on the zona pellucida, we hypothesize that the hyperosmotic effect of sucrose reduced the potential for laser-induced cytotoxic thermal damage to the underlying oocytes. With appropriate preparation and cautious application, our results indicate that LZD-assisted IVF is a safe, efficacious and efficient assisted reproductive technology for deriving mutant mouse lines with male factor infertility and subfertility caused by sperm-zona penetration defects.

The τCstF-64 polyadenylation protein controls genome expression in testis

The τCstF-64 polyadenylation protein (gene symbol Cstf2t) is a testis-expressed orthologue of CstF-64. Mice in which Cstf2t was knocked out had a phenotype that was only detected in meiotic and postmeiotic male germ cells, giving us the opportunity to examine CstF-64 function in an isolated developmental system. We performed massively parallel clonally amplified sequencing of cDNAs from testes of wild type and Cstf2t^−/− mice. These results revealed that loss of τCstF-64 resulted in large-scale changes in patterns of genome expression. We determined that there was a significant overrepresentation of RNAs from introns and intergenic regions in testes of Cstf2t^−/− mice, and a concomitant use of more distal polyadenylation sites. We observed this effect particularly in intronless small genes, many of which are expressed retroposons that likely co-evolved with τCstF-64. Finally, we observed overexpression of long interspersed nuclear element (LINE) sequences in Cstf2t^−/− testes. These results suggest that τCstF-64 plays a role in 3′ end determination and transcription termination for a large range of germ cell-expressed genes.

Evolution of genes involved in gamete interaction: evidence for positive selection, duplications and losses in vertebrates

Genes encoding proteins involved in sperm-egg interaction and fertilization exhibit a particularly fast evolution and may participate in prezygotic species isolation [1], [2]. Some of them (ZP3, ADAM1, ADAM2, ACR and CD9) have individually been shown to evolve under positive selection [3], [4], suggesting a role of positive Darwinian selection on sperm-egg interaction. However, the genes involved in this biological function have not been systematically and exhaustively studied with an evolutionary perspective, in particular across vertebrates with internal and external fertilization. Here we show that 33 genes among the 69 that have been experimentally shown to be involved in fertilization in at least one taxon in vertebrates are under positive selection. Moreover, we identified 17 pseudogenes and 39 genes that have at least one duplicate in one species. For 15 genes, we found neither positive selection, nor gene copies or pseudogenes. Genes of teleosts, especially genes involved in sperm-oolemma fusion, appear to be more frequently under positive selection than genes of birds and eutherians. In contrast, pseudogenization, gene loss and gene gain are more frequent in eutherians. Thus, each of the 19 studied vertebrate species exhibits a unique signature characterized by gene gain and loss, as well as position of amino acids under positive selection. Reflecting these clade-specific signatures, teleosts and eutherian mammals are recovered as clades in a parsimony analysis. Interestingly the same analysis places Xenopus apart from teleosts, with which it shares the primitive external fertilization, and locates it along with amniotes (which share internal fertilization), suggesting that external or internal environmental conditions of germ cell interaction may not be the unique factors that drive the evolution of fertilization genes. Our work should improve our understanding of the fertilization process and on the establishment of reproductive barriers, for example by offering new leads for experiments on genes identified as positively selected.

Spermatogenetic but not immunological defects in mice lacking the τCstF-64 polyadenylation protein

Alternative polyadenylation controls expression of genes in many tissues including immune cells and male germ cells. The τCstF-64 polyadenylation protein is expressed in both cell types, and we previously showed that Cstf2t, the gene encoding τCstF-64 was necessary for spermatogenesis and fertilization. Here we examine consequences of τCstF-64 loss in both germ cells and immune cells. Spermatozoa from Cstf2t null mutant (Cstf2t(-/-)) mice of ages ranging from 60 to 108 days postpartum exhibited severe defects in motility and morphology that were correlated with a decrease in numbers of round spermatids. Spermatozoa in these mice also displayed severe morphological defects at every age, especially in the head and midpiece. In the testicular epithelium, we saw normal numbers of cells in earlier stages of spermatogenesis, but reduced numbers of round spermatids in Cstf2t(-/-) mice. Although Leydig cell numbers were normal, we did observe reduced levels of plasma testosterone in the knockout animals, suggesting that reduced androgen might also be contributing to the Cstf2t(-/-) phenotype. Finally, while τCstF-64 was expressed in a variety of immune cell types in wild type mice, we did not find differences in secreted IgG or IgM or changes in immune cell populations in Cstf2t(-/-) mice, suggesting that τCstF-64 function in immune cells is either redundant or vestigial. Together, these data show that τCstF-64 function is primarily to support spermatogenesis, but only incidentally to support immune cell function.