Kinesin motor KIFC1 is required for tubulin acetylation and actin-dependent spindle migration in mouse oocyte meiosis.

Mammalian oocyte maturation is a unique asymmetric division, which is mainly because of actin-based spindle migration to the cortex. In the present study, we report that a kinesin motor KIFC1, which is associated with microtubules for the maintenance of spindle poles in mitosis, is also involved in actin dynamics in murine oocyte meiosis, co-localizing with microtubules during mouse oocyte maturation. Depletion of KIFC1 caused the failure of polar body extrusion, and we found that meiotic spindle formation and chromosome alignment were disrupted. This might be because of the effects of KIFC1 on HDAC6 and NAT10-based tubulin acetylation, which further affected microtubule stability. Mass spectroscopy analysis revealed that KIFC1 also associated with several actin nucleation factors and we found that KIFC1 was essential for the distribution of actin filaments, which further affected spindle migration. Depletion of KIFC1 leaded to aberrant expression of formin 2 and the ARP2/3 complex, and endoplasmic reticulum distribution was also disturbed. Exogenous KIFC1 mRNA supplement could rescue these defects. Taken together, as well as its roles in tubulin acetylation, our study reported a previously undescribed role of kinesin KIFC1 on the regulation of actin dynamics for spindle migration in mouse oocytes.

Arf6 GTPase deficiency leads to porcine oocyte quality decline during aging.

Arf6 is a member of ADP-ribosylation factor (Arf) family, which is widely implicated in the regulation of multiple physiological processes including endocytic recycling, cytoskeletal organization, and membrane trafficking during mitosis. In this study, we investigated the potential relationship between Arf6 and aging-related oocyte quality, and its roles on organelle rearrangement and cytoskeleton dynamics in porcine oocytes. Arf6 expressed in porcine oocytes throughout meiotic maturation, and it decreased in aged oocytes. Disruption of Arf6 led to the failure of cumulus expansion and polar body extrusion. Further analysis indicated that Arf6 modulated ac-tubulin for meiotic spindle organization and microtubule stability. Besides, Arf6 regulated cofilin phosphorylation and fascin for actin assembly, which further affected spindle migration, indicating the roles of Arf6 on cytoskeleton dynamics. Moreover, the lack of Arf6 activity caused the dysfunction of Golgi and ER for protein synthesis and signal transduction. Mitochondrial dysfunction was also observed in Arf6-deficient porcine oocytes, which was supported by the increased ROS level and abnormal membrane potential. In conclusion, our results reported that insufficient Arf6 was related to aging-induced oocyte quality decline through spindle organization, actin assembly, and organelle rearrangement in porcine oocytes.

Mcrs1 regulates G2/M transition and spindle assembly during mouse oocyte meiosis.

Microspherule protein 1 (Mcrs1) is a component of the nonspecific lethal (NSL) complex and the chromatin remodeling INO80 complex, which participates in transcriptional regulation during mitosis. Here, we investigate the roles of Mcrs1 during female meiosis in mice. We demonstrate that Mcrs1 is a novel regulator of the meiotic G2/M transition and spindle assembly in mouse oocytes. Mcrs1 is present in the nucleus and associates with spindle poles and chromosomes of oocytes during meiosis I. Depletion of Mcrs1 alters HDAC2-mediated H4K16ac, H3K4me2, and H3K9me2 levels in nonsurrounded nucleolus (NSN)-type oocytes, and reduces CDK1 activity and cyclin B1 accumulation, leading to G2/M transition delay. Furthermore, Mcrs1 depletion results in abnormal spindle assembly due to reduced Aurora kinase (Aurka and Aurkc) and Kif2A activities, suggesting that Mcrs1 also plays a transcription-independent role in regulation of metaphase I oocytes. Taken together, our results demonstrate that the transcription factor Mcrs1 has important roles in cell cycle regulation and spindle assembly in mouse oocyte meiosis.

Kinesin KIF3A regulates meiotic progression and spindle assembly in oocyte meiosis.

Kinesin family member 3A (KIF3A) is a microtubule-oriented motor protein that belongs to the kinesin-2 family for regulating intracellular transport and microtubule movement. In this study, we characterized the critical roles of KIF3A during mouse oocyte meiosis. We found that KIF3A associated with microtubules during meiosis and depletion of KIF3A resulted in oocyte maturation defects. LC-MS data indicated that KIF3A associated with cell cycle regulation, cytoskeleton, mitochondrial function and intracellular transport-related molecules. Depletion of KIF3A activated the spindle assembly checkpoint, leading to metaphase I arrest of the first meiosis. In addition, KIF3A depletion caused aberrant spindle pole organization based on its association with KIFC1 to regulate expression and polar localization of NuMA and γ-tubulin; and KIF3A knockdown also reduced microtubule stability due to the altered microtubule deacetylation by histone deacetylase 6 (HDAC6). Exogenous Kif3a mRNA supplementation rescued the maturation defects caused by KIF3A depletion. Moreover, KIF3A was also essential for the distribution and function of mitochondria, Golgi apparatus and endoplasmic reticulum in oocytes. Conditional knockout of epithelial splicing regulatory protein 1 (ESRP1) disrupted the expression and localization of KIF3A in oocytes. Overall, our results suggest that KIF3A regulates cell cycle progression, spindle assembly and organelle distribution during mouse oocyte meiosis.

NAMPT regulates mitochondria function and lipid metabolism during porcine oocyte maturation.

Oocyte maturation defect can lead to maternal reproduction disorder. NAMPT is a rate-limiting enzyme in mammalian NAD+ biosynthesis pathway, which can regulate a variety of cellular metabolic processes including glucose metabolism and DNA damage repair. However, the function of NAMPT in porcine oocytes remains unknown. In this study, we showed that NAMPT involved into multiple cellular events during oocyte maturation. NAMPT expressed during all stages of porcine oocyte meiosis, and inhibition of NAMPT activity caused the cumulus expansion and polar body extrusion defects. Mitochondrial dysfunction was observed in NAMPT-deficient porcine oocytes, which showed decreased membrane potential, ATP and mitochondrial DNA content, increased oxidative stress level and apoptosis. We also found that NAMPT was essential for spindle organization and chromosome arrangement based on Ac-tubulin. Moreover, lack of NAMPT activity caused the increase of lipid droplet and affected the imbalance of lipogenesis and lipolysis. In conclusion, our study indicated that lack of NAMPT activity affected porcine oocyte maturation through its effects on mitochondria function, spindle assembly and lipid metabolism.

Kinesin KIFC3 is essential for microtubule stability and cytokinesis in oocyte meiosis.

KIFC3 is a member of Kinesin-14 family motor proteins, which play a variety of roles such as centrosome cohesion, cytokinesis, vesicles transportation and cell proliferation in mitosis. Here, we investigated the functional roles of KIFC3 in meiosis. Our findings demonstrated that KIFC3 exhibited expression and localization at centromeres during metaphase I, followed by translocation to the midbody at telophase I throughout mouse oocyte meiosis. Disruption of KIFC3 activity resulted in defective polar body extrusion. We observed aberrant meiotic spindles and misaligned chromosomes, accompanied by the loss of kinetochore-microtubule attachment, which might be due to the failed recruitment of BubR1/Bub3. Coimmunoprecipitation data revealed that KIFC3 plays a crucial role in maintaining the acetylated tubulin level mediated by Sirt2, thereby influencing microtubule stability. Additionally, our findings demonstrated an interaction between KIFC3 and PRC1 in regulating midbody formation during telophase I, which is involved in cytokinesis regulation. Collectively, these results underscore the essential contribution of KIFC3 to spindle assembly and cytokinesis during mouse oocyte meiosis.

Deoxynivalenol exposure disturbs the cytoplasmic maturation in porcine oocytes.

Deoxynivalenol (DON) is a secondary metabolite of Fusarium fungi and belonged to trichothecenes, and it widely presents in various food commodities. Previous studies have highlighted its potent toxicity, adversely affecting the growth, development, and reproductive in both humans and animals. However, the potential impact of DON on porcine oocyte organelles remains elusive. In present study, we delved into the toxic effects of DON on mitochondria, endoplasmic reticulum, Golgi during the porcine oocyte maturation. Our findings revealed that DON exposure significantly impeded granulosa cell diffusion and the expulsion of the first polar body. Additionally, mitochondrial fluorescence intensity and membrane potential underwent notable alterations under DON exposure. Notably, lysosomal fluorescence intensity decreased significantly, suggesting protein degradation and potential autophagy, which was further corroborated by the enhanced fluorescence intensity of LC3. Furthermore, endoplasmic reticulum fluorescence intensity declined, and DON exposure elevated endoplasmic reticulum stress levels, evident from the upregulated expression of GRP78. Concurrently, we observed disruption in the fusiform cortex distribution of the Golgi apparatus, characterized by reduced Golgi apparatus fluorescence intensity and GM130 expression. Collectively, our results indicate that DON exposure profoundly affects the fundamental functions of porcine oocyte organelles during meiosis and maturation.

Benzo[a]pyrene exposure disrupts the organelle distribution and function of mouse oocytes.

Benzo[a]pyrene (BaP) is a polycyclic aromatic hydrocarbon compound that is generated during combustion processes, and is present in various substances such as foods, tobacco smoke, and burning emissions. BaP is extensively acknowledged as a highly carcinogenic substance to induce multiple forms of cancer, such as lung cancer, skin cancer, and stomach cancer. Recently it is shown to adversely affect the reproductive system. Nevertheless, the potential toxicity of BaP on oocyte quality remains unclear. In this study, we established a BaP exposure model via mouse oral gavage and found that BaP exposure resulted in a notable decrease in the ovarian weight, number of GV oocytes in ovarian, and oocyte maturation competence. BaP exposure caused ribosomal dysfunction, characterized by a decrease in the expression of RPS3 and HPG in oocytes. BaP exposure also caused abnormal distribution of the endoplasmic reticulum (ER) and induced ER stress, as indicated by increased expression of GRP78. Besides, the Golgi apparatus exhibited an abnormal localization pattern, which was confirmed by the GM130 localization. Disruption of vesicle transport processes was observed by the abnormal expression and localization of Rab10. Additionally, an enhanced lysosome and LC3 fluorescence intensity indicated the occurrence of protein degradation in oocytes. In summary, our results suggested that BaP exposure disrupted the distribution and functioning of organelles, consequently affecting the developmental competence of mouse oocytes.

Effects of Regulating Hippo and Wnt on the Development and Fate Differentiation of Bovine Embryo.

The improvement of in vitro embryo development is a gateway to enhance the output of assisted reproductive technologies. The Wnt and Hippo signaling pathways are crucial for the early development of bovine embryos. This study investigated the development of bovine embryos under the influence of a Hippo signaling agonist (LPA) and a Wnt signaling inhibitor (DKK1). In this current study, embryos produced in vitro were cultured in media supplemented with LPA and DKK1. We comprehensively analyzed the impact of LPA and DKK1 on various developmental parameters of the bovine embryo, such as blastocyst formation, differential cell counts, YAP fluorescence intensity and apoptosis rate. Furthermore, single-cell RNA sequencing (scRNA-seq) was employed to elucidate the in vitro embryonic development. Our results revealed that LPA and DKK1 improved the blastocyst developmental potential, total cells, trophectoderm (TE) cells and YAP fluorescence intensity and decreased the apoptosis rate of bovine embryos. A total of 1203 genes exhibited differential expression between the control and LPA/DKK1-treated (LD) groups, with 577 genes upregulated and 626 genes downregulated. KEGG pathway analysis revealed significant enrichment of differentially expressed genes (DEGs) associated with TGF-beta signaling, Wnt signaling, apoptosis, Hippo signaling and other critical developmental pathways. Our study shows the role of LPA and DKK1 in embryonic differentiation and embryo establishment of pregnancy. These findings should be helpful for further unraveling the precise contributions of the Hippo and Wnt pathways in bovine trophoblast formation, thus advancing our comprehension of early bovine embryo development.

Kinesin KIF15 regulates tubulin acetylation and spindle assembly checkpoint in mouse oocyte meiosis.

Microtubule dynamics ensure multiple cellular events during oocyte meiosis, which is critical for the fertilization and early embryo development. KIF15 (also termed Hklp2) is a member of kinesin-12 family motor proteins, which participates in Eg5-related bipolar spindle formation in mitosis. In present study, we explored the roles of KIF15 in mouse oocyte meiosis. KIF15 expressed during oocyte maturation and localized with microtubules. Depletion or inhibition of KIF15 disturbed meiotic cell cycle progression, and the oocytes which extruded the first polar body showed a high aneuploidy rate. Further analysis showed that disruption of KIF15 did not affect spindle morphology but resulted in chromosome misalignment. This might be due to the reduced stability of the K-fibers, which further induced the loss of kinetochore-microtubule attachment and activated spindle assembly checkpoint, showing with the failed release of Bub3 and BubR1. Based on mass spectroscopy analysis and coimmunoprecipitation data we showed that KIF15 was responsible for recruiting HDAC6, NAT10 and SIRT2 to maintain the acetylated tubulin level, which further affected tubulin acetylation for microtubule stability. Taken together, these results suggested that KIF15 was essential for the microtubule acetylation and cell cycle control during mouse oocyte meiosis.

Aflatoxin B1 impairs porcine oocyte quality via disturbing intracellular membrane system and ATP production.

Aflatoxin is the most common type of mycotoxins in contaminated corn, peanuts and rice, which affects the livestock and ultimately endangers human health. Aflatoxin is reported to have carcinogenicity, mutation, growth retardation, immunosuppression and reproductive toxicity. In present study we reported the causes for the declined porcine oocyte quality under aflatoxin exposure. We set up an in vitro exposure model and showed that aflatoxin B1 disturbed cumulus cell expansion and oocyte polar body extrusion. We found that aflatoxin B1 exposure disrupted ER distribution and elevated the expression of GRP78, indicating the occurrence of ER stress, and the increased calcium storage also confirmed this. Besides, the structure of cis-Golgi apparatus, another intracellular membrane system was also affected, showing with decreased GM130 expression. The oocytes under aflatoxin B1 exposure showed aberrant lysosome accumulation and higher LAMP2 expression, a marker for lysosome membrane protection, and this might be due to the aberrant mitochondria function with low ATP production and the increase of apoptosis, since we found that BAX expression increased, and ribosomal protein which is also an apoptosis-related factor RPS3 decreased. Taken together, our study revealed that aflatoxin B1 impairs intracellular membrane system ER, Golgi apparatus, lysosome and mitochondria function to affect porcine oocyte maturation quality.

Toxicity of the Mycotoxin Deoxynivalenol on Early Cleavage of Mouse Embryos by Fluorescence Intensity Analysis.

Deoxynivalenol is a mycotoxin, produced by Fusarium from contaminated corn, wheat, and other grains, that induces multiple effects in humans and animals, including cytotoxic, genotoxic, immunotoxic, and carcinogenic effects. Recent studies show that deoxynivalenol also affects the reproductive system of mammals, including oocyte quality. However, the effects of deoxynivalenol on early embryonic development have not been reported. In this study, fluorescence intensity analysis was used to show that deoxynivalenol disrupted the first cleavage of the zygote. The high deoxynivalenol dose disturbed the movement of the pronucleus after fertilization, while the low deoxynivalenol dose caused aberrant spindle morphology during the metaphase of the first cleavage. Further analysis showed that the reactive oxygen species level increased in the deoxynivalenol-exposed two-cell embryos, indicating oxidative stress. Moreover, deoxynivalenol caused DNA damage in the embryos, as positive γH2A.X signals were detected in the nucleus. These events led to the early apoptosis of mouse embryos, which was confirmed by autophagy. Taken together, our study provides evidence for the toxicity of deoxynivalenol during early embryonic development in the mouse model.

SIRT3 Regulates Levels of Deacetylated SOD2 to Prevent Oxidative Stress and Mitochondrial Dysfunction During Oocyte Maturation in Pigs.

Mammalian oocyte maturation relies on mitochondrial ATP production, but this can lead to damaging reactive oxygen species (ROS). SIRT3, a mitochondrial sirtuin, plays a critical role in regulating mitochondrial redox balance in mouse oocytes under stress; however, its specific roles in porcine oocytes remain unclear. In this study, we utilized the SIRT3 inhibitor 3-TYP to investigate SIRT3's importance in porcine oocyte maturation. Our findings revealed that SIRT3 is expressed in porcine oocytes and its inhibition leads to maturation failure. This was evident through reduced polar body extrusion, arrested cell cycle, as well as disrupted spindle organization and actin distribution. Furthermore, SIRT3 inhibition resulted in a decrease in mitochondrial DNA copy numbers, disruption of mitochondrial membrane potential, and reduced ATP levels, all indicating impaired mitochondrial function in porcine oocytes. Additionally, the primary source of damaged mitochondria was associated with decreased levels of deacetylated superoxide dismutase 2 (SOD2) after SIRT3 inhibition, which led to ROS accumulation and oxidative stress-induced apoptosis. Taken together, our results suggest that SIRT3 regulates the levels of deacetylated SOD2 to maintain redox balance and preserve mitochondrial function during porcine oocyte maturation, with potential implications for improving pig reproduction.

Age-related SUMOylation of PLK1 is essential to meiosis progression in mouse oocytes.

Polo like kinase 1 (PLK1) is a protein kinase involved in regulating the spindle assembly and cell cycle control in mammalian oocytes. SUMOylation, one way of post-translational modification, regulates oocyte meiosis by controlling several substrates. However, the relation between PLK1 and SUMOylation in oocytes is still unknown. In this study, we investigated that whether PLK1 was modified by SUMOylation in oocytes and its potential relationship with age-related meiotic abnormalities. We showed that PLK1 had colocalization and protein interaction with Small Ubiquitin-Like Modifier (SUMO)-1 and SUMO-2/3 in mouse oocytes, indicating that PLK1 could be modified by SUMO-1 and SUMO-2/3. Overexpression of PLK1 SUMOylation site mutants PLK1K178R and PLK1K191R caused the increase of the abnormal spindle rate of oocytes and the decline of the first polar body extrusion rate with the abnormal localization of PLK1, suggesting that the SUMOylation modification of PLK1 is essential for normal meiosis in oocytes. Compared with young mice, the expression of PLK1 protein increased and the expression of SUMO-1 and SUMO-2/3 protein decreased in the oocytes of aged mice, indicating that the SUMOylation of PLK1 might be related to the mouse aging. Therefore, our data suggested that PLK1 could be SUMOylated by SUMO-1 and SUMO-2/3 in mouse oocytes and SUMOylation of PLK1 regulated the meiosis progression of oocytes which was related with aging.

Rab23/Kif17 regulate meiotic progression in oocytes by modulating tubulin acetylation and actin dynamics.

Cytoskeletal dynamics are involved in multiple cellular processes during oocyte meiosis, including spindle organization, actin-based spindle migration and polar body extrusion. Here, we report that the vesicle trafficking protein Rab23, a GTPase, drives the motor protein Kif17, and that this is important for spindle organization and actin dynamics during mouse oocyte meiosis. GTP-bound Rab23 accumulated at the spindle and promoted migration of Kif17 to the spindle poles. Depletion of Rab23 or Kif17 caused polar body extrusion failure. Further analysis showed that depletion of Rab23/Kif17 perturbed spindle formation and chromosome alignment, possibly by affecting tubulin acetylation. Kif17 regulated tubulin acetylation by associating with αTAT and Sirt2, and depletion of Kif17 altered expression of these proteins. Moreover, depletion of Kif17 decreased the level of cytoplasmic actin, which abrogated spindle migration to the cortex. The tail domain of Kif17 associated with constituents of the RhoA-ROCK-LIMK-cofilin pathway to modulate assembly of actin filaments. Taken together, our results demonstrate that the Rab23-Kif17-cargo complex regulates tubulin acetylation for spindle organization and drives actin-mediated spindle migration during meiosis.

Nivalenol affects spindle formation and organelle functions during mouse oocyte maturation.

Oocyte maturation is essential for fertilization and early embryo development, and proper organelle functions guarantee this process to maintain high-quality oocytes. The type B trichothecene nivalenol (NIV) is a mycotoxin produced by Fusarium oxysporum and is commonly found in contaminated food. NIV intake affect growth, the immune system, and the female reproductive system. Here, we investigated NIV toxicity on mouse oocyte quality. Transcriptome analysis results showed that NIV exposure altered the expression of multiple genes involved in spindle formation and organelle function in mouse oocytes, indicating its toxicity on mouse oocyte maturation. Further analysis indicated that NIV exposure disrupted spindle structure and chromosome alignment, possibly through tubulin acetylation. NIV exposure induced aberrant mitochondria distribution and reduced mitochondria number, mitochondria membrane potential (MMP), and ATP levels. In addition, NIV caused the abnormal distribution of the Golgi apparatus and altered the expression of the vesicle trafficking protein Rab11. ER distribution was also disturbed under NIV exposure, indicating the effects of NIV on protein modification and transport in oocytes. Thus, our results demonstrated that NIV exposure affected spindle structure and organelles function in mouse oocytes.

Exposure to nonylphenol impairs oocyte quality via the induction of organelle defects in mice.

Nonylphenol (NP) is an environmental endocrine disruptor, which is mainly used in the production of surfactants, lubricants, additives, pesticides, and emulsifiers. NP is widely found in sewage and sludge, which has neurotoxicity, immunotoxicity, metabolic toxicity and reproductive toxicity. In this study, we investigated the effects of NP exposure on mammalian oocyte quality from organelle aspects with mouse in vivo model. The results showed that the ovarian weight of mice exposed to 500 µg/L NP for 4 weeks increased and the development ability of oocytes decreased, showing with lower rate of polar body extrusion. Further analysis indicated that exposure to NP caused the abnormal distribution of mitochondria, following with altered membrane potential drop. NP exposure disrupted the spindle periphery localization of ER, and affected the expression of GRP78 for the induction of ER stress. Moreover, Golgi apparatus fragment in the oocytes was observed, and Rab11-based vesicle transport was disturbed. We also found that the protein degradation might be affected since LAMP2 expression increased and LC3 decreased, indicating the lysosome and autophagy dysfunction. Taken together, our findings suggested that the exposure of NP to mice in vivo affected oocyte quality through its effects on the distribution and function of organelles.

Single-cell transcriptome analysis reveals that maternal obesity affects DNA repair, histone methylation, and autophagy level in mouse embryos.

Obesity causes many reproductive dysfunctions such as reduced conception, infertility, and early pregnancy loss, and this is largely due to the negative effects of obesity on oocyte and embryo quality. In the present study, we employed single-cell RNA transcriptome sequencing to investigate the potential causes for the maternal obesity effects on mouse embryos. Our results showed that the 4-cell and morula/blastocyst rates were all significantly decreased during embryo development in obese mice. Genome-wide analysis indicated that obesity altered the expression of more than 1100 genes in 2-cell embryos, including the genes which were related to the p53 signaling pathway and apoptosis. Further analysis showed that the expression of 47 genes related to DNA damage was changed, and a positive γH2A signal and the altered expression of Rad51 and Tex15 were observed in the obese embryos. Obesity also affected histone methylation, shown by the decrease of the H3K4-me2 level. Besides this, we observed the occurrence of autophagy and apoptosis in the embryos of obese mice. There were 42 genes that were related to autophagy/apoptosis that showed aberrant expression, and the positive LC3 signal and the decrease of Clec16a, Rraga, and Atg10 level were also observed. In summary, our study suggested that obesity affected early embryonic development by inducing DNA damage, aberrant histone methylation, and autophagy levels in mice.

FASCIN regulates actin assembly for spindle movement and polar body extrusion in mouse oocyte meiosis.

During mouse oocyte meiotic maturation, actin filaments play multiple roles in meiosis such as spindle migration and cytokinesis. FASCIN is shown to be an actin-binding and bundling protein, making actin filaments tightly packed and parallel-aligned, and FASCIN is involved in several cellular processes like adhesion and migration. FASCIN is also a potential prognostic biomarker and therapeutic target for the treatment of metastatic disease. However, little is known about the functions of FASCIN in oocyte meiosis. In the present study, we knocked down the expression of FASCIN, and our results showed that FASCIN was essential for oocyte maturation. FASCIN was all expressed in the different stages of oocyte meiosis, and it mainly localized at the cortex of oocytes from the GV stage to the MII stage and showed a similar localization pattern with actin and DAAM1. Depletion of FASCIN affected the extrusion of the first polar body, and we also observed that some oocytes extruded from the large polar bodies. This might have resulted from the defects of actin assembly, which further affected the meiotic spindle positioning. In addition, we showed that inhibition of PKC activity decreased FASCIN expression, indicating that FASCIN might be regulated by PKC. Taken together, our results provided evidence for the important role of FASCIN on actin filaments for spindle migration and polar body extrusion in mouse oocyte meiosis.

Mps1 controls spindle assembly, SAC, and DNA repair in the first cleavage of mouse early embryos.

Monopolar spindle-1 (Mps1) is a critical interphase regulator that also involves into the spindle assembly checkpoint for the cell cycle control in both mitosis and meiosis. However, the functions of Mps1 during mouse early embryo development is still unclear. In this study, we reported the important roles of Mps1 in the first cleavage of mouse embryos. Our data indicated that the loss of Mps1 activity caused precocious cleavage of zygotes to 2-cell embryos; however, prolonged culture disturbed the early embryo development to the blastocyst. We found that the spindle organization was disrupted after Mps1 inhibition, and the chromosomes were misaligned in the first cleavage. Moreover, the kinetochore-microtubule attachment was lost and Aurora B failed to accumulate to the kinetochores, indicating that the spindle assembly checkpoint (SAC) was activated. Furthermore, the inhibition of Mps1 activity resulted in an increase of DNA damage, which further induced oxidative stress, showing with positive γ-H2A.X signal and increased reactive oxygen species level. Ultimately, irreparable DNA damage and oxidative stress-activated apoptosis and autophagy, which was confirmed by the positive Annexin-V signal and increased autophagosomes. Taken together, our data indicated that Mps1 played important roles in the control of SAC and DNA repair during mouse early embryo development.