Human X-linked Intellectual Disability Factor CUL4B Is Required for Post-meiotic Sperm Development and Male Fertility

Molecular insights into sperm head shaping and its role in human male fertility

BACKGROUND

Sperm head shaping, controlled by the acrosome-acroplaxome-manchette complex, represents a significant morphological change during spermiogenesis and involves numerous proteins expressed in a spatially and temporally specific manner. Defects in sperm head shaping frequently lead to teratozoospermia concomitant with oligozoospermia and asthenozoospermia, but the pathogenic mechanism underlying sperm head shaping, and its role in male infertility, remain poorly understood.

OBJECTIVE AND RATIONALE

This review aims to summarize the mechanism underlying sperm head shaping, reveal the relationship between gene defects associated with sperm head shaping and male infertility in humans and mice, and explore potential clinical improvements in ICSI treatment.

SEARCH METHODS

We searched the PubMed database for articles published in English using the keyword 'sperm head shaping' in combination with the following terms: 'acrosome formation', 'proacrosomal vesicles (PAVs)', 'manchette', 'perinuclear theca (PT)', 'chromatin condensation', 'linker of nucleoskeleton and cytoskeleton (LINC) complex', 'histone-to-protamine (HTP) transition', 'male infertility', 'ICSI', and 'artificial oocyte activation (AOA)'. The selected publications until 1 August 2024 were critically summarized, integrated, and thoroughly discussed, and the irrelevant literature were excluded.

OUTCOMES

A total of 6823 records were retrieved. After careful screening, integrating relevant literature, and excluding articles unrelated to the topic of this review, 240 articles were ultimately included in the analysis. Firstly, we reviewed the important molecular events and structures integral to sperm head shaping, including PAV formation to fusion, acrosome attachment to the nucleus, structure and function of the manchette, PT, chromatin condensation, and HTP transition. Then, we set forth human male infertility associated with sperm head shaping and identified genes related to sperm head shaping resulting in teratozoospermia concomitant with oligozoospermia and asthenozoospermia. Finally, we summarized the outcomes of ICSI in cases of male infertility resulting from mutations in the genes associated with sperm head shaping, as well as the ICSI outcomes through AOA for infertile men with impaired sperm head.

WIDER IMPLICATIONS

Understanding the molecular mechanisms of sperm head shaping and its relationship with human male infertility holds profound clinical implications, which may contribute to risk prediction, genetic diagnosis, and the potential treatment of human male infertility.

GABA transporter 1 is a promising drug target for CUL4B mutation-associated epilepsy

Cullin 4B (CUL4B) is the scaffold protein in the CUL4B-RING E3 ubiquitin ligase (CRL4B) complex. Loss-of-function mutations in the human CUL4B gene result in syndromic X-linked intellectual disability (XLID). In addition to intellectual disability, patients with CUL4B mutations exhibit epilepsy. To date, the mechanism underlying epilepsy associated with CUL4B mutation has not been elucidated. Here, we show that male mice with Cul4b deleted in the nervous system are more susceptible to both pentylenetetrazole (PTZ)- and kainic acid (KA)-induced epilepsy and exhibit spontaneous epilepsy without any chemical inducers. We identify the CRL4B complex as an E3 ubiquitin ligase that targets GABA transporter 1 (GAT1). CUL4B deletion in male mice results in GAT1 accumulation and increased GABA reuptake, leading to impaired GABA-mediated inhibitory synaptic transmission. Treating CUL4B-deficient mice with the GAT1 inhibitor tiagabine effectively reverses the increased susceptibility to chemical-induced epilepsy and attenuates spontaneous epilepsy without the use of chemical inducers. We further confirm the role of CUL4B in the regulation of GAT1 levels and GABA uptake in neurons and astrocytes differentiated from induced pluripotent stem cells (iPSCs) derived from patients with CUL4B loss-of-function mutations. Our work reveals a novel mechanism underlying the pathogenesis of epilepsy and identifies a promising drug target for treating CUL4B mutation-associated epilepsy.

E3 Siah ubiquitin ligase regulates dichotomous spermatogenesis in Sitotroga cerealella

Spermatogenesis in Lepidoptera holds significant importance due to its unique process of dichotomous spermatogenesis, yielding eupyrene and apyrene spermatozoa through a complex molecular mechanism. While E3 ubiquitin ligases are known to play vital roles in spermatogenesis across various processes, their functions in dichotomous spermatogenesis remain less known. We utilized the RNAi, biochemical and microscopic procedures to unravel the function of ScE3 Siah in dichotomous spermatogenesis of adult Sitotroga cerealella. In S. cerealella E3 ligase Siah predominantly expressed in adult tissues. Knockdown of ScE3 Siah leads to disruptions in testes and sperm morphology, affecting the structure of eupyrene and apyrene sperm bundles and causing defective ultrastructure in eupyrene sperm. This disruption results in a reduction in the number of dichotomous sperms and significantly reduces their motility. Moreover, ScE3 Siah knockdown inhibits the transfer and motility of dichotomous sperm, impacting spermatophore formation in females and ultimately reducing egg production. Understanding the role of ScE3 Siah is not only crucial for comprehending the complex processes involved in dichotomous spermatogenesis and fertilization but also provides an avenue for sustainable pest control management.

Cullin 4B-RING E3 ligase negatively regulates the immunosuppressive capacity of mesenchymal stem cells by suppressing iNOS

Mesenchymal stem cells (MSCs) are multipotent stem cells that can exert immunomodulatory capacity upon stimulation with pro-inflammatory cytokines. Our previous work has identified Cullin 4B (CUL4B), a scaffold protein in the CUL4B-RING E3 ligase (CRL4B) complex, as a key regulator in the differentiation of MSCs. Here, we demonstrate the critical role of CUL4B in regulating the immunosuppressive function of MSCs. When stimulated with pro-inflammatory cytokines, MSCs lacking CUL4B display enhanced immunosuppressive capacity, which is mediated by the elevated inducible nitric oxide synthase (iNOS). TGF-β signaling can suppress iNOS by inhibiting its transcription as well as promoting its protein degradation. We show that the CRL4B complex cooperates with PRC2 complex and HDACs to repress transcription of Dlx1 and Pmepa1, two inhibitors of TGF-β signaling, leading to decreased expression and accelerated degradation of iNOS. Our study unveils the CRL4B complex as a potential therapeutic target in promoting the immunosuppressive capacity of MSCs.

CUL4B protects kidneys from acute injury by restraining p53/PAI-1 signaling

Acute kidney injury (AKI) caused by nephrotoxins, ischemia reperfusion (IR) or sepsis is associated with high morbidity and mortality. Unveiling new mechanisms underlying AKI can help develop new therapeutic strategy. Cullin 4B (CUL4B) is a scaffold protein in the CUL4B-RING E3 ubiquitin ligase (CRL4B) complex. Here, we demonstrate that CUL4B can protect kidneys from acute injury induced by cisplatin and IR. CUL4B is upregulated in mouse tubular epithelial cells (TECs) after cisplatin treatment or IR. Loss of CUL4B in kidneys exacerbates renal injury, inflammation, and apoptosis of TECs caused by cisplatin and IR. Transcriptome analysis reveals that Cul4b deficiency enhances injury-induced PAI-1 expression. CUL4B suppresses PAI-1 expression by promoting polyubiquitination and degradation of p53. Inhibition of either PAI-1 or p53 can prevent the aggravated renal injury and inflammation caused by loss of CUL4B. Our work has identified the kidney-protective role of CUL4B against acute injury.

The X-linked intellectual disability gene CUL4B is critical for memory and synaptic function

Cullin 4B (CUL4B) is the scaffold protein in the CUL4B-RING E3 ubiquitin ligase (CRL4B) complex. Loss-of-function mutations in the human CUL4B gene lead to syndromic X-linked intellectual disability (XLID). Till now, the mechanism of intellectual disability caused by CUL4B mutation still needs to be elucidated. In this study, we used single-nucleus RNA sequencing (snRNA-seq) to investigate the impact of CUL4B deficiency on the transcriptional programs of diverse cell types. The results revealed that depletion of CUL4B resulted in impaired intercellular communication and elicited cell type-specific transcriptional changes relevant to synapse dysfunction. Golgi-Cox staining of brain slices and immunostaining of in vitro cultured neurons revealed remarkable synapse loss in CUL4B-deficient mice. Ultrastructural analysis via transmission electron microscopy (TEM) showed that the width of the synaptic cleft was significantly greater in CUL4B-deficient mice. Electrophysiological experiments found a decrease in the amplitude of AMPA receptor-mediated EPSCs in the hippocampal CA1 pyramidal neurons of CUL4B-deficient mice. These results indicate that depletion of CUL4B in mice results in morphological and functional abnormalities in synapses. Furthermore, behavioral tests revealed that depletion of CUL4B in the mouse nervous system results in impaired spatial learning and memory. Taken together, the findings of this study reveal the pathogenesis of neurological disorders associated with CUL4B mutations and promote the identification of therapeutic targets that can halt synaptic abnormalities and preserve memory in individuals.

CRL4B complex-mediated H2AK119 monoubiquitination restrains Th1 and Th2 cell differentiation

CD4+ T helper (Th) cell differentiation is regulated by lineage-specific expression of transcription factors, which is tightly associated with epigenetic modifications, including histone acetylation and methylation. However, the factors regulating histone modifications involved in Th cell differentiation remain largely unknown. We herein demonstrated a critical role of Cullin 4B (CUL4B) in restricting Th1 and Th2 cell differentiation. CUL4B, which is assembled into the CUL4B-RING E3 ligase (CRL4B) complex, participates in various physiological and developmental processes through epigenetic repression of transcription. Depletion of Cul4b in CD4+ T cells enhanced Th1 and Th2 cell differentiation. In vivo, an aggravated Th2 response caused by the absence of CUL4B was observed in a murine asthma model. Mechanistically, the CRL4B complex promoted monoubiquitination at H2AK119 (H2AK119ub1) and polycomb repressive complex 2 (PRC2)-mediated trimethylation at H3K27 (H3K27me3) at Tbx21 and Maf and consequently repressed their expression during Th cell differentiation. Our study suggests that CRL4B complex-mediated H2AK119ub1 deposition functions to prevent the aberrant expression of Th1 and Th2 lineage-specific genes.

Cullin 4b-RING ubiquitin ligase targets IRGM1 to regulate Wnt signaling and intestinal homeostasis

Hierarchical organization of intestine relies on the self-renewal and tightly regulated differentiation of intestinal stem cells (ISCs). Although signals like Wnt are known to sustain the continued intestinal renewal by maintaining ISCs activity and lineage commitment, molecular mechanisms underlying ISCs ‘stemness’ and supportive niche have not been well understood. Here, we found that CUL4B-RING ubiquitin ligase (CRL4B) regulates intestinal homeostasis by targeting immunity-related GTPase family M member 1 (IRGM1) for proteasomal degradation. CUL4B was mainly expressed at ISCs zone. Deletion of Cul4b led to reduced self-renewal of ISCs and a decreased lineage differentiation towards secretory progenitors through downregulated Wnt signals. Besides, Cul4b-null mice exhibited impaired Paneth cells number and structure. Mechanistically, CRL4B complex were associated with WD40 proteins and targeted IRGM1 at K270 for ubiquitination and proteosomal degradation. Impaired intestinal function caused by CUL4B deletion was rescued by down-regulation of its substrate IRGM1. Our results identified CUL4B as a novel regulator of ISCs and revealed a new 26 S proteasome degradation mechanism in intestine self-renewal and lineage commitment.

Ubiquitin ligases: guardians of mammalian development

Mammalian development demands precision. Millions of molecules must be properly located in temporal order, and their function regulated, to orchestrate important steps in cell cycle progression, apoptosis, migration and differentiation, to shape developing embryos. Ubiquitin and its associated enzymes act as cellular guardians to ensure precise spatio-temporal control of key molecules during each of these important cellular processes. Loss of precision results in numerous examples of embryological disorders or even cancer. This Review discusses the crucial roles of E3 ubiquitin ligases during key steps of early mammalian development and their roles in human disease, and considers how new methods to manipulate and exploit the ubiquitin regulatory machinery - for example, the development of molecular glues and PROTACs - might facilitate clinical therapy.

Proteolysis in Reproduction: Lessons From Gene-Modified Organism Studies

The physiological roles of proteolysis are not limited to degrading unnecessary proteins. Proteolysis plays pivotal roles in various biological processes through cleaving peptide bonds to activate and inactivate proteins including enzymes, transcription factors, and receptors. As a wide range of cellular processes is regulated by proteolysis, abnormalities or dysregulation of such proteolytic processes therefore often cause diseases. Recent genetic studies have clarified the inclusion of proteases and protease inhibitors in various reproductive processes such as development of gonads, generation and activation of gametes, and physical interaction between gametes in various species including yeast, animals, and plants. Such studies not only clarify proteolysis-related factors but the biological processes regulated by proteolysis for successful reproduction. Here the physiological roles of proteases and proteolysis in reproduction will be reviewed based on findings using gene-modified organisms.

DDB1- and CUL4-associated factor 8 plays a critical role in spermatogenesis

Cullin-RING E3 ubiquitin ligase (CRL)-4 is a member of the large CRL family in eukaryotes. It plays important roles in a wide range of cellular processes, organismal development, and physiological and pathological conditions. DDB1- and CUL4-associated factor 8 (DCAF8) is a WD40 repeat-containing protein, which serves as a substrate receptor for CRL4. The physiological role of DCAF8 is unknown. In this study, we constructed Dcaf8 knockout mice. Homozygous mice were viable with no noticeable abnormalities. However, the fertility of Dcaf8-deficient male mice was markedly impaired, consistent with the high expression of DCAF8 in adult mouse testis. Sperm movement characteristics, including progressive motility, path velocity, progressive velocity, and track speed, were significantly lower in Dcaf8 knockout mice than in wild-type (WT) mice. However, the total motility was similar between WT and Dcaf8 knockout sperm. More than 40% of spermatids in Dcaf8 knockout mice showed pronounced morphological abnormalities with typical bent head malformation. The acrosome and nucleus of Dcaf8 knockout sperm looked similar to those of WT sperm. In vitro tests showed that the fertilization rate of Dcaf8 knockout mice was significantly reduced. The results demonstrated that DCAF8 plays a critical role in spermatogenesis, and DCAF8 is a key component of CRL4 function in the reproductive system.

Regulation of Stem Cells by Cullin-RING Ligase

Stem cells can remain quiescent, self-renewal, and differentiate into many types of cells and even cancer stem cells. The coordination of these complex processes maintains the homeostasis of the organism. Ubiquitination is an important posttranslational modification process that regulates protein stability and activity. The ubiquitination levels of stem cell-associated proteins are closely related with stem cell characteristics. Cullin-RING Ligases (CRLs) are the largest family of E3 ubiquitin ligases, accounting for approximately 20% of proteins degraded by proteasome. In this review, we discuss the role of CRLs in stem cell homeostasis, self-renewal, and differentiation and expound their ubiquitination substrates. In addition, we also discuss the effect of CRLs on the formation of cancer stem cells that may provide promising therapy strategies for cancer.

CRL4 Ubiquitin Pathway and DNA Damage Response

DNA damage occurs in a human cell at an average frequency of 10,000 incidences per day by means of external and internal culprits, damage that triggers sequential cellular responses and stalls the cell cycle while activating specific DNA repair pathways. Failure to remove DNA lesions would compromise genomic integrity, leading to human diseases such as cancer and premature aging. If DNA damage is extensive and cannot be repaired, cells undergo apoptosis. DNA damage response (DDR) often entails posttranslational modifications of key DNA repair and DNA damage checkpoint proteins, including phosphorylation and ubiquitination. Cullin-RING ligase 4 (CRL4) enzyme has been found to target multiple DDR proteins for ubiquitination. In this chapter, we will discuss key repair and checkpoint proteins that are subject to ubiquitin-dependent regulation by members of the CRL4 family during ultraviolet light (UV)-induced DNA damage.

Embryonic Cul4b is important for epiblast growth and location of primitive streak layer cells

Cul4b-null (Cul4bΔ/Y) mice undergo growth arrest and degeneration during the early embryonic stages and die at E9.5. The pathogenic causes of this lethality remain incompletely characterized. However, it has been hypothesized that the loss of Cul4b function in extraembryonic tissues plays a key role. In this study, we investigated possible causes of death for Cul4b-null embryos, particularly in regard to the role of embryonic Cul4b. First, we show that the loss of embryonic Cul4b affects the growth of the inner cell mass in vitro and delays epiblast development during the gastrulation period at E6.5~E7.5 in vivo, as highlighted by the absence of the epiblastic transcription factor Brachyury from E6.5~E7.5. Additionally, at E7.5, strong and laterally expanded expression of Eomes and Fgf8 signaling was detected. Sectioning of these embryos showed disorganized primitive streak layer cells. Second, we observed that Mash2-expressing cells were present in the extraembryonic tissues of Cul4b-deficient embryos at E6.5 but were absent at E7.5. In addition, the loss of Cul4b resulted in decreased expression of cyclin proteins, which are required for the cell cycle transition from G1 to S. Taken together, these observations suggest that the embryonic expression of Cul4b is important for epiblast growth during E6.5~E7.5, and the loss of Cul4b results in either delayed growth of the epiblast or defective localization of primitive streak layer cells. As a result, the signaling activity mediated by the epiblast for subsequent ectoplacental cone development is affected, with the potential to induce growth retardation and lethality in Cul4bΔ/Y embryos.

Identification of KIAA1210 as a novel X-chromosome-linked protein that localizes to the acrosome and associates with the ectoplasmic specialization in testes

Cell junctions are necessary for spermatogenesis, and there are numerous types of junctions in testis, such as blood–testis barrier, intercellular bridge, and ectoplasmic specialization (ES). The details of their functions and construction are still unknown. To identify a novel protein essential to the function of a cell junction, we enriched testis membrane protein and analyzed it using a proteomics approach. Here, we report a novel ES protein, which is encoded on the X chromosome and an ortholog of hypothetical human protein KIAA1210. KIAA1210 is expressed in testis predominantly, localized to the sex body in spermatocyte, acrosome, and near ES. Moreover, KIAA1210 possesses a topoisomerase 2 (TOP2)-associated protein PAT1 domain, a herpes simplex virus 1 (HSV-1) large tegument protein UL36 hypothetical domain, and a provisional DNA translocase FtsK domain. Using IP-proteomics with specific antibody to KIAA1210, we identified proteins including TOP2 isoforms as components of a complex with KIAA1210, in cell junctions in testis. The interaction between KIAA1210 and TOP2 was confirmed by two different proteomic analyses. Furthermore, immunofluorescence showed that KIAA1210 and TOP2B co-localize around the sex body in spermatocyte, apical ES, and residual bodies in elongated spermatids. Our findings suggest that KIAA1210 may be essential cell junction protein that interacts with TOP2B to regulate the dynamic change of chromatin structures during spermiogenesis.

Deletion of DDB1- and CUL4- associated factor-17 (Dcaf17) gene causes spermatogenesis defects and male infertility in mice

DDB1– and CUL4–associated factor 17 (Dcaf17) is a member of DCAF family genes that encode substrate receptor proteins for Cullin-RING E3 ubiquitin ligases, which play critical roles in many cellular processes. To unravel the function of DCAF17, we performed expression profiling of Dcaf17 in different tissues of wild type mouse by qRT-PCR and generated Dcaf17 knockout mice by gene targeting. Expression profiling of Dcaf17 showed highest expression in testis. Analyses of Dcaf17 transcripts during post-natal development of testis at different ages displayed gradual increase in Dcaf17 mRNA levels with the age. Although Dcaf17 disruption did not have any effect on female fertility, Dcaf17 deletion led to male infertility due to abnormal sperm development. The Dcaf17^−/− mice produced low number of sperm with abnormal shape and significantly low motility. Histological examination of the Dcaf17^−/− testis revealed impaired spermatogenesis with presence of vacuoles and sloughed cells in the seminiferous tubules. Disruption of Dcaf17 caused asymmetric acrosome capping, impaired nuclear compaction and abnormal round spermatid to elongated spermatid transition. For the first time, these data indicate that DCAF17 is essential for spermiogenesis.

Function of RAD6B and RNF8 in spermatogenesis

Histone ubiquitination regulates sperm formation and is important for nucleosome removal during spermatogenesis. RNF8 is an E3 ubiquitin ligase, and RAD6B is an E2 ubiquitin-conjugating enzyme. Both proteins participate in DNA damage repair processes via histone ubiquitination. Loss of RNF8 or RAD6B can lead to sterility in male mice. However, the specific mechanisms regulating these ubiquitin-mediated processes are unclear. In this study, we found that RNF8 knockout mice were either subfertile or sterile based on the numbers of offspring they produced. We explored the mechanism by which RAD6B and RNF8 knockouts cause infertility in male mice and compared the effects of their loss on spermatogenesis. Our results demonstrate that RAD6B can polyubiquitinate histones H2 A and H2B. In addition, RNF8 was shown to monoubiquitinate histones H2 A and H2B. Furthermore, we observed that absence of histone ubiquitination was not the only reason for infertility. Senescence played a role in intensifying male sterility by affecting the number of germ cells during spermatogenesis. In summary, both histone ubiquitination and senescence play important roles in spermatogenesis.

Nuclear organization during in vitro differentiation of porcine mesenchymal stem cells (MSCs) into adipocytes

Differentiation of progenitor cells into adipocytes is accompanied by remarkable changes in cell morphology, cytoskeletal organization, and gene expression profile. Mature adipocytes are filled with a large lipid droplet and the nucleus tends to move to the cell periphery. It was hypothesized that the differentiation process is also associated with changes of nuclear organization. The aim of this study was to determine the number and distribution of selected components of nuclear architecture during porcine in vitro adipogenesis. The pig is an important animal model sharing many similarities to humans at the anatomical, physiological, and genetic levels and has been recognized as a good model for human obesity. Thus, understanding how cellular structures important for fundamental nuclear processes may be altered during adipocyte differentiation is of great importance. Mesenchymal stem cells (MSCs) were derived from bone marrow (BM-MSCs) and adipose tissue (AD-MSCs) and were cultured for 7 days in the adipogenic medium. A variable differentiation potential of these cell populations towards adipogenic lineage was observed, and for further study, a comparative characteristic of the nuclear organization in BM-MSCs and AD-MSCs was performed. Nuclear substructures were visualized by indirect immunofluorescence (nucleoli, nuclear speckles, PML bodies, lamins, and HP1α) or fluorescence in situ hybridization (telomeres) on fixed cells at 0, 3, 5, and 7 days of differentiation. Comprehensive characterization of these structures, in terms of their number, size, dynamics, and arrangement in three-dimensional space of the nucleus, was performed. It was found that during differentiation of porcine MSCs into adipocytes, changes of nuclear organization occurred and concerned: (1) the nuclear size and shape; (2) reduced lamin A/C expression; and (3) reorganization of chromocenters. Other elements of nuclear architecture such as nucleoli, SC-35 nuclear speckles, and telomeres showed no significant changes when compared to undifferentiated and mature fat cells. In addition, the presence of a low number of PML bodies was characteristic of the studied porcine mesenchymal stem cell adipogenesis system. It has been shown that the arrangement of selected components of nuclear architecture was very similar in MSCs derived from different sources, whereas adipocyte differentiation involves nuclear reorganization. This study adds new data on nuclear organization during adipogenesis using the pig as a model organism.

Functional analysis of Cullin 3 E3 ligases in tumorigenesis

Cullin 3-RING ligases (CRL3) play pivotal roles in the regulation of various physiological and pathological processes, including neoplastic events. The substrate adaptors of CRL3 typically contain a BTB domain that mediates the interaction between Cullin 3 and target substrates to promote their ubiquitination and subsequent degradation. The biological implications of CRL3 adaptor proteins have been well described where they have been found to play a role as either an oncogene, tumor suppressor, or can mediate either of these effects in a context-dependent manner. Among the extensively studied CRL3-based E3 ligases, the role of the adaptor protein SPOP (speckle type BTB/POZ protein) in tumorigenesis appears to be tissue or cellular context dependent. Specifically, SPOP acts as a tumor suppressor via destabilizing downstream oncoproteins in many malignancies, especially in prostate cancer. However, SPOP has largely an oncogenic role in kidney cancer. Keap1, another well-characterized CRL3 adaptor protein, likely serves as a tumor suppressor within diverse malignancies, mainly due to its specific turnover of its downstream oncogenic substrate, NRF2 (nuclear factor erythroid 2-related factor 2). In accordance with the physiological role the various CRL3 adaptors exhibit, several pharmacological agents have been developed to disrupt its E3 ligase activity, therefore blocking its potential oncogenic activity to mitigate tumorigenesis.

Expression of markers for germ cells and oocytes in cow dermal fibroblast treated with 5-azacytidine and cultured in differentiation medium containing BMP2, BMP4 or follicular fluid

This study aims to investigate the effect 5-azacytidine (5-Aza) during induction of pluripotency in bovine fibroblasts and to evaluate the effects of BMP2, BMP4 or follicular fluid in the differentiation of reprogrammed fibroblasts in primordial germ cells and oocytes. It also analysis the mRNA levels for OCT4, NANOG, REX, SOX2, VASA, DAZL, cKIT, SCP3, ZPA and GDF9 after culturing 5-Aza treated fibroblasts in the different tested medium. Dermal fibroblasts were cultured and exposed to 0.5, 1.0 or 2.0 μM of 5-Aza for 18 h, 36 h or 72 h. Then, the cells were cultured in DMEM/F12 supplemented with 10 ng/ml BMP2, 10 ng/ml BMP4 or 5% follicular fluid. After culture, morphological characteristics, viability and gene expression were evaluated by qPCR. Treatment of skin fibroblasts with 2.0 μM 5-Aza for 72 h significantly increased expression of mRNAs for SOX2, OCT4, NANOG and REX. The culture in medium supplemented with BMP2, BMP4 or follicular fluid for 7 or 14 days induced formation of oocyte-like cells, as well as the expression of markers for germ cells and oocyte. In conclusion, treatment of bovine skin-derived fibroblasts with 2.0 μM 5-Aza for 72 h induces the expression of pluripotency factors. Culturing these cells in differentiation medium supplemented with BMP2, BMP4 or follicular fluid induces morphological changes and promotes expression of markers for germ cells, meiosis and oocyte.