CRL4DCAF13 E3 ubiquitin ligase targets MeCP2 for degradation to prevent DNA hypermethylation and ensure normal transcription in growing oocytes.

The DNA methylation is gradually acquired during oogenesis, a process sustained by successful follicle development. However, the functional roles of methyl-CpG-binding protein 2 (MeCP2), an epigenetic regulator displaying specifical binding with methylated DNA, remains unknown in oogenesis. In this study, we found MeCP2 protein was highly expressed in primordial and primary follicle, but was almost undetectable in secondary follicles. However, in aged ovary, MeCP2 protein is significantly increased in both oocyte and granulosa cells. Overexpression of MeCP2 in growing oocyte caused transcription dysregulation, DNA hypermethylation, and genome instability, ultimately leading to follicle growth arrest and apoptosis. MeCP2 is targeted by DCAF13, a substrate recognition adaptor of the Cullin 4-RING (CRL4) E3 ligase, and polyubiquitinated for degradation in both cells and oocytes. Dcaf13-null oocyte exhibited an accumulation of MeCP2 protein, and the partial rescue of follicle growth arrest induced by Dcaf13 deletion was observed following MeCP2 knockdown. The RNA-seq results revealed that large amounts of genes were regulated by the DCAF13-MeCP2 axis in growing oocytes. Our study demonstrated that CRL4DCAF13 E3 ubiquitin ligase targets MeCP2 for degradation to ensure normal DNA methylome and transcription in growing oocytes. Moreover, in aged ovarian follicles, deceased DCAF13 and DDB1 protein were observed, indicating a potential novel mechanism that regulates ovary aging.

Ovulatory signal-triggered chromatin remodeling in ovarian granulosa cells by HDAC2 phosphorylation activation-mediated histone deacetylation.

BACKGROUND: Epigenetic reprogramming is involved in luteinizing hormone (LH)-induced ovulation; however, the underlying mechanisms are largely unknown. RESULTS: We here observed a rapid histone deacetylation process between two waves of active transcription mediated by the follicle-stimulating hormone (FSH) and the LH congener human chorionic gonadotropin (hCG), respectively. Analysis of the genome-wide H3K27Ac distribution in hCG-treated granulosa cells revealed that a rapid wave of genome-wide histone deacetylation remodels the chromatin, followed by the establishment of specific histone acetylation for ovulation. HDAC2 phosphorylation activation coincides with histone deacetylation in mouse preovulatory follicles. When HDAC2 was silenced or inhibited, histone acetylation was retained, leading to reduced gene transcription, retarded cumulus expansion, and ovulation defect. HDAC2 phosphorylation was associated with CK2α nuclear translocation, and inhibition of CK2α attenuated HDAC2 phosphorylation, retarded H3K27 deacetylation, and inactivated the ERK1/2 signaling cascade. CONCLUSIONS: This study demonstrates that the ovulatory signal erases histone acetylation through activation of CK2α-mediated HDAC2 phosphorylation in granulosa cells, which is an essential prerequisite for subsequent successful ovulation.

HucMSC-EVs Facilitate In Vitro Development of Maternally Aged Preantral Follicles and Oocytes.

Follicle developmental capacity and oocyte quality decline with advanced maternal age. Extracellular vesicles from human umbilical cord mesenchymal stem cells (HucMSC-EVs) act as a potential therapeutic product in the treatment of age-related ovarian dysfunction. In vitro culture (IVC) of preantral follicles is a useful method for understanding the mechanism of follicle development and is a promising means for improving female fertility. However, whether HucMSC-EVs have beneficial effects on aged follicle development during IVC has not yet been reported. Our research demonstrated that follicular development with single-addition withdrawal of HucMSC-EVs was better than that with continuous treatment with HucMSC-EVs. HucMSC-EVs facilitated the survival and growth of follicles, promoted the proliferation of granulosa cells (GCs), and improved the steroid hormone secretion of GCs during IVC of aged follicles. Both GCs and oocytes could uptake HucMSC-EVs. Moreover, we observed elevated cellular transcription in GCs and oocytes after treatment with HucMSC-EVs. The RNA sequencing (RNA-seq) results further validated that the differentially expressed genes are related to the promotion of GC proliferation, cell communication, and oocyte spindle organization. Additionally, the aged oocytes displayed a higher maturation rate, presented less aberrant spindle morphology, and expressed a higher level of the antioxidant protein Sirtuin 1 (SIRT1) after treatment with HucMSC-EVs. Our findings suggested that HucMSC-EVs can improve the growth and quality of aged follicles and oocytes in vitro through the regulation of gene transcription, which provides evidence for HucMSC-EVs as potential therapeutic reagents to restore female fertility with advanced age.

Decreased histidine-rich glycoprotein and increased complement C4-B protein levels in follicular fluid predict the IVF outcomes of recurrent spontaneous abortion.

BACKGROUND: Recurrent spontaneous abortion (RSA) is a common and complicated pregnancy-related disease that lacks a suitable biomarker to predict its recrudescence. METHODS: Tandem mass tag (TMT) analysis was conducted to obtain quantitative proteomic profiles in follicular fluid from patients with a history of RSA and from control group. ELISA validation of candidate differentially expressed proteins was conducted in a larger group of patients. RESULTS: A total of 836 proteins were identified by TMT analysis; 51 were upregulated and 47 were downregulated in follicular fluid from cases of RSA versus control group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis revealed several important pathways were enriched, involving a dysregulated immunoglobulin Fc receptor signaling pathway and overactivated complement cascade pathways. ELISA validated the differential expression of two proteins, histidine-rich globulin (HRG) and complement C4-B (C4B), which were downregulated and upregulated, respectively, in follicular fluid of patients with RSA. We performed receiver operating characteristic curve analysis of the ELISA results with the outcomes of current IVF cycles as classification variables. The area under the curve results for HRG alone, C4B alone and HRG-C4B combined were 0.785, 0.710 and 0.895, respectively. CONCLUSIONS: TMT analysis identified 98 differentially expressed proteins in follicular fluid from patients with RSA, indicating follicle factors that act as early warning factors for the occurrence of RSA. Among them, HRG and C4B provide candidate markers to predict the clinical outcomes of IVF/ICSI cycles, and the potential for modeling an early detection system for RSA.

Mutations in OOEP and NLRP5 identified in infertile patients with early embryonic arrest.

The subcortical maternal complex (SCMC), composed of several maternal-effect genes, is vital for the development of oocytes and early embryos. Variants of SCMC-encoding genes (NLRP2, NLRP5, TLE6, PADI6, and KHDC3L, but not OOEP and ZBED3) are associated with human oocyte maturation dysfunction, fertilization failure, and early embryonic arrest. In this study, we enrolled 118 Chinese patients who experienced recurrent preimplantation embryonic arrest during assisted reproductive technology treatments and performed whole-exome sequencing. We discovered compound heterozygous missense variants (c.110G>C and c.109C>G) in the OOEP gene in one patient who experienced recurrent preimplantation embryonic arrest. Arrested embryos from this affected patient were analyzed by single-cell RNA sequencing, which showed a downregulated transcriptome. In addition, six novel NLRP5 variants (c.971T>A, c.3341T>C, c.1575_1576delAG, c.1830_1831delGT, c.1202C>T, and c.2378T>G) were identified in four patients with arrested and severely fragmented embryos. These suspicious mutations were examined by in vitro studies in HEK293T cells. Western blot analysis and immunofluorescence experiments showed that OOEP and partial NLRP5 mutations caused decreased protein levels. Our findings first demonstrated that biallelic variants in OOEP gene could also cause human early embryonic arrest, similar to other SCMC components. We expanded the genetic mutation spectrum of SCMC genes related to early embryogenesis in humans, especially early embryonic arrest.

Characterisation of Disease Patterns of Dermatomyositis with Different Initial Manifestations.

Purpose: To determine the characteristics and prognoses of dermatomyositis (DM) by comparing the difference in initial symptoms. Patients and Methods: A retrospective analysis was performed on the patients diagnosed with DM from 1 January 2019 to 1 January 2021. Based on the firstly presented symptoms, patients were divided into five groups, namely rash group, muscle weakness group, arthritis group, respiratory symptom group and atypical symptom group. Clinical and laboratory data were recorded. All patients were followed up until 31 May 2021. Results: In total 136 DM patients, rash (40%) was the most common initial symptom, followed by respiratory symptoms (22%), arthritis (20%), muscle weakness (10%) and atypical symptoms (8%). Rash group and atypical group had a higher positive rate of anti-TIF1γ antibodies than arthritis group and respiratory symptom group (P < 0.05). Respiratory symptom and arthritis groups had a higher positive rate of anti-Ro52 antibodies than rash and muscle weakness groups (P < 0.05). Respiratory group had a higher incidence of ILD than rash and atypical groups. The FVC and DLCO in respiratory group were significantly lower than rash group, arthritis group and atypical group (P < 0.05). The survival rate of rash group was significantly higher than muscle weakness group and arthritis group (P < 0.05). Conclusion: DM patients with different initial manifestations had different myositis antibodies and prognoses.

Biallelic variants in MOS cause large polar body in oocyte and human female infertility.

STUDY QUESTION: What is the genetic basis of female infertility involving abnormal oocyte morphology with the production of a large first polar body (PB1)? SUMMARY ANSWER: The homozygous missense variant (c.791C>G) and compound missense variants (c.596A>T and c.875C>T) in MOS proto-oncogene, serine/threonine kinase (MOS) (Online Mendelian Inheritance in Man (OMIM) reference: 190060; NM_005372.1) are responsible for abnormal oocyte morphology with the production of a large PB1 to cause infertility in women. WHAT IS KNOWN ALREADY: MOS, an oocyte-specific gene, encodes a serine/threonine-protein kinase that directly phosphorylates mitogen-activated protein kinase (MAPK) kinase (MEK) to activate MAPK (also called extracellular-signal-regulated kinase (ERK)) signal cascade in the oocyte. Female mice lacking Mos remained viable, but infertile because of oocyte symmetric division, spontaneous parthenogenetic activation and early embryonic arrest. Recently, two independent studies demonstrated that female infertility with early embryonic arrest and fragmentation can be caused by biallelic mutations in MOS. However, so far, MOS variants have not been associated with the phenotype of large PB1 extrusion in human oocytes to contribute to female infertility. STUDY DESIGN, SIZE, DURATION: Two independent infertile families characterized by the presence of large PB1 in oocytes were recruited between December 2020 and February 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: Genomic DNA was extracted from the peripheral blood samples of the subjects for whole-exome sequencing. Pedigree analysis was validated by Sanger sequencing. Then, the pathogenic effects of the MOS variants on MOS protein properties and ERK1/2 activation were determined in HEK293 cells and mouse oocytes. MAIN RESULTS AND THE ROLE OF CHANCE: We identified three rare missense variants in MOS, including a homozygous missense variant (c.791C>G) from Patient 1 in Family 1 and two compound missense variants (c.596A>T and c.875C>T) from twin sisters in Family 2. The MOS variants followed a recessive inheritance pattern in infertile patients. All three patients displayed a high percentage of large PB1 extrusion in the oocytes. The three MOS variants could not activate MEK1/2 and ERK1/2 in oocytes and HEK293 cells. In addition, when compared with wild-type MOS, the MOS variants decreased the MOS protein level and attenuated the binding capacity with MEK1. Microinjection of wild-type human MOS complementary RNAs (cRNAs) reversed the symmetric division of oocytes after siMos treatment. In contrast, the three MOS variants demonstrated no rescuing ability. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Owing to the scarcity of human oocyte samples and the associated ethical restrictions, we could not perform the rescue attempt for the study patients. WIDER IMPLICATIONS OF THE FINDINGS: Our findings expand the genetic and phenotypic spectrum of MOS variants in causing female infertility. Our study findings facilitate the early genetic diagnosis of abnormal oocyte morphology characterized as large PB1 that eventually causes infertility in women. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the National Natural Science Foundation of China (82071640 and 82001633), Natural Science Foundation of Zhejiang Province (LD22C060001), the Key Projects Jointly Constructed by the Ministry and the Province of Zhejiang Medical and Health Science and Technology Project (WKJ-ZJ-2005), China Postdoctoral Science Foundation (2020M682575 and 2021T140198), the Changsha Municipal Natural Science Foundation (kq2007022) and Hunan Provincial Grant for Innovative Province Construction (2019SK4012). None of the authors declare any competing interests. TRIAL REGISTRATION NUMBER: N/A.

DCAF13 promotes breast cancer cell proliferation by ubiquitin inhibiting PERP expression.

Evolutionarily conserved DDB1-and CUL4-associated factor 13 (DCAF13) is a recently discovered substrate receptor for the cullin RING-finger ubiquitin ligase 4 (CRL4) E3 ubiquitin ligase that regulates cell cycle progression. DCAF13 is overexpressed in many cancers, although its role in breast cancer is currently elusive. In this study we demonstrate that DCAF13 is overexpressed in human breast cancer and that its overexpression closely correlates with poor prognosis, suggesting that DCAF13 may serve as a diagnostic marker and therapeutic target. We knocked down DCAF13 in breast cancer cell lines using CRISPR/Cas9 and found that DCAF13 deletion markedly reduced breast cancer cell proliferation, clone formation, and migration both in vitro and in vivo. In addition, DCAF13 deletion promoted breast cancer cell apoptosis and senescence, and induced cell cycle arrest in the G1/S phase. Genome-wide RNAseq analysis and western blotting revealed that loss of DCAF13 resulted in both mRNA and protein accumulation of p53 apoptosis effector related to PMP22 (PERP). Knockdown of PERP partially reversed the hampered cell proliferation induced by DCAF13 knockdown. Co-immunoprecipitation assays revealed that DCAF13 and DNA damage-binding protein 1 (DDB1) directly interact with PERP. Overexpression of DDB1 significantly increased PERP polyubiquitination, suggesting that CRL4DCAF13 E3 ligase targets PERP for ubiquitination and proteasomal degradation. In conclusion, DCAF13 and the downstream effector PERP occupy key roles in breast cancer proliferation and potentially serve as prognostics and therapeutic targets.

Clinical characteristics of anti-isoleucyl-tRNA synthetase antibody associated syndrome and comparison with different patient cohorts.

OBJECTIVES: This study aimed to analyse the clinical features of anti-isoleucyl-tRNA synthetase (OJ) antibodies in Chinese patients and to compare with previously published cohorts. We reviewed the clinical data of anti-OJ antibody positive patients, including their long-term follow-up. RESULTS: Anti-OJ antibodies were present in 10 of 1269 (0.8%) patients with idiopathic inflammatory myopathies (IIMs), and 10/320 (3.1%) patients with anti-synthetase syndrome (ASS). Of the anti-OJ antibody-positive patients, 90% had interstitial lung disease (ILD), of whom three (30%) developed rapidly progressive ILD (RP-ILD). Half (50%) of the patients were febrile and developed myocardial involvement; 40% of patients experienced myositis, mechanic's hands and arthritis. Compared to the anti-Jo-1 group, the levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in the anti-OJ antibody-positive group were higher (p<0.05). From a review of the literature regarding the clinical features of anti-OJ, fever was more common in the eastern cohort (41.7% vs. 8.3%, p=0.002), whereas patients in western countries were more likely to develop arthritis (20.9% vs. 58.1%, p=0.001). With complete follow-up of the present cohort, 80% improved with treatment, including one patient who underwent lung transplant. CONCLUSIONS: The anti-OJ antibody occurred infrequently in Chinese patients, ILD was the major clinical feature, but myocardial injury was also a prominent associated complication. Anti-OJ positive patients were responsive to treatment.

Biallelic mutations in MOS cause female infertility characterized by human early embryonic arrest and fragmentation.

Early embryonic arrest and fragmentation (EEAF) is a common phenomenon leading to female infertility, but the genetic determinants remain largely unknown. The Moloney sarcoma oncogene (MOS) encodes a serine/threonine kinase that activates the ERK signaling cascade during oocyte maturation in vertebrates. Here, we identified four rare variants of MOS in three infertile female individuals with EEAF that followed a recessive inheritance pattern. These MOS variants encoded proteins that resulted in decreased phosphorylated ERK1/2 level in cells and oocytes, and displayed attenuated rescuing effects on cortical F-actin assembly. Using oocyte-specific Erk1/2 knockout mice, we verified that MOS-ERK signal pathway inactivation in oocytes caused EEAF as human. The RNA sequencing data revealed that maternal mRNA clearance was disrupted in human mature oocytes either with MOS homozygous variant or with U0126 treatment, especially genes relative to mitochondrial function. Mitochondrial dysfunction was observed in oocytes with ERK1/2 deficiency or inactivation. In conclusion, this study not only uncovers biallelic MOS variants causes EEAF but also demonstrates that MOS-ERK signaling pathway drives human oocyte cytoplasmic maturation to prevent EEAF.

Novel WEE2 compound heterozygous mutations identified in patients with fertilization failure or poor fertilization.

PURPOSE: To study associations between novel WEE2 mutations and patients with fertilization failure or poor fertilization. METHODS: Thirty-one Chinese patients who underwent treatment with assisted reproductive technology and suffered from repeated (at least two times) total fertilization failure (TFF) or a low fertilization rate were enrolled. Genomic DNA was extracted from patients for whole-exome sequencing. Suspicious mutations were validated by Sanger sequencing. WEE2 protein levels in oocytes from affected patients were examined by immunofluorescence. Disruptive effects of mutations on WEE2 protein stability, subcellular localization, and kinase function were analyzed through western blotting, immunofluorescence, and flow cytometry in HeLa cells. RESULTS: Three of thirty-one (9.6%) enrolled patients had six compound heterozygous mutations of the WEE2 gene, and three of them were reported here for the first time (c.115_116insT, c.756_758delTGA, and c.C1459T). Oocytes from affected patients showed decreased WEE2 immunofluorescence signals. In vitro experiments showed that the mutant WEE2 gene caused reduced WEE2 protein levels or cellular compartment translocation in HeLa cells, leading to decreased levels of the phosphorylated Cdc2 protein. Compared with the wild-type WEE2 protein, the mutant WEE2 proteins were also found to have different effects on the cell cycle. CONCLUSION: Three novel compound heterozygous WEE2 variants were found in patients with pronucleus formation failure. This study provides new evidence that WEE2 mutations result in loss of function, which could result in fertilization failure.

A Type of Atypical AIEgen Used for One-Photon/Two-Photon Targeted Imaging in Live Cells.

Aggregation-induced emission luminogens (AIEgens) with a large electron donor and acceptor (D-A) conjugated system have been widely used in the development of organic light emitting diodes (OLEDs), chemosensors, and bioimaging materials due to their excellent properties such as high quantum yields, long emission wavelengths, controllable luminescence lifetimes, and nonlinear optics (NLO) properties. However, most of the AIE materials have been derived from limited classic AIE cores such as tetraphenylethene (TPE) and tetraphenylpyrazine (TPP), and thus, tedious syntheses or later modifications toward those AIEgens have always been unavoidable. In this report, a type of atypical AIEgens (designated as ASIQs) composed of large conjugated structures with a natural electron D-A system is disclosed, which shows large Stokes shifts, high photostabilities, excellent cell permeabilities, low biotoxicities, and good two-photon excited capacities, making them suitable for applications of one-photon/two-photon targeted imaging in live cells. In short, this work offers a type of atypical AIEgens which will possibly become an ideal platform leading to more structurally diverse and functionally excellent AIE-based luminescent materials.

The CRL4-DCAF13 ubiquitin E3 ligase supports oocyte meiotic resumption by targeting PTEN degradation.

Cullin ring-finger ubiquitin ligase 4 (CRL4) has multiple functions in the maintenance of oocyte survival and meiotic cell cycle progression. DCAF13, a novel CRL4 adaptor, is essential for oocyte development. But the mechanisms by which CRL4-DCAF13 supports meiotic maturation remained unclear. In this study, we demonstrated that DCAF13 stimulates the meiotic resumption-coupled activation of protein synthesis in oocytes, partially by maintaining the activity of PI3K signaling pathway. CRL4-DCAF13 targets the polyubiquitination and degradation of PTEN, a lipid phosphatase that inhibits PI3K pathway as well as oocyte growth and maturation. Dcaf13 knockout in oocytes caused decreased CDK1 activity and impaired meiotic cell cycle progression and chromosome condensation defects. As a result, chromosomes fail to be aligned at the spindle equatorial plate, the spindle assembly checkpoint is activated, and most Dcaf13 null oocytes are arrested at the prometaphase I. The DCAF13-dependent PTEN degradation mechanism fits in as a missing link between CRL4 ubiquitin E3 ligase and PI3K pathway, both of which are crucial for translational activation during oocyte GV-MII transition.

Metal-free sulfonyl radical-initiated cascade cyclization to access sulfonated indolo[1,2-a]quinolines.

A metal-free cascade reaction was developed for the synthesis of indolo[1,2-a]quinoline derivatives from arylsulfonyl hydrazides and 1-(2-(arylethynyl)phenyl)indoles in the presence of TBAI/TBHP. Impressively, these products exhibit excellent fluorescence properties, which is promising for cell imaging.

Mammalian nucleolar protein DCAF13 is essential for ovarian follicle maintenance and oocyte growth by mediating rRNA processing.

During mammalian oocyte growth, chromatin configuration transition from the nonsurrounded nucleolus (NSN) to surrounded nucleolus (SN) type plays a key role in the regulation of gene expression and acquisition of meiotic and developmental competence by the oocyte. Nonetheless, the mechanism underlying chromatin configuration maturation in oocytes is poorly understood. Here we show that nucleolar protein DCAF13 is an important component of the ribosomal RNA (rRNA)-processing complex and is essential for oocyte NSN-SN transition in mice. A conditional knockout of Dcaf13 in oocytes led to the arrest of oocyte development in the NSN configuration, follicular atresia, premature ovarian failure, and female sterility. The DCAF13 deficiency resulted in pre-rRNA accumulation in oocytes, whereas the total mRNA level was not altered. Further exploration showed that DCAF13 participated in the 18S rRNA processing in growing oocytes. The lack of 18S rRNA because of DCAF13 deletion caused a ribosome assembly disorder and then reduced global protein synthesis. DCAF13 interacted with a protein of the core box C/D ribonucleoprotein, fibrillarin, i.e., a factor of early pre-rRNA processing. When fibrillarin was knocked down in the oocytes from primary follicles, follicle development was inhibited as well, indicating that an rRNA processing defect in the oocyte indeed stunts chromatin configuration transition and follicle development. Taken together, these results elucidated the in vivo function of novel nucleolar protein DCAF13 in maintaining mammalian oogenesis.

CNOT6L couples the selective degradation of maternal transcripts to meiotic cell cycle progression in mouse oocyte.

Meiotic resumption-coupled degradation of maternal transcripts occurs during oocyte maturation in the absence of mRNA transcription. The CCR4-NOT complex has been identified as the main eukaryotic mRNA deadenylase. In vivo functional and mechanistic information regarding its multiple subunits remains insufficient. Cnot6l, one of four genes encoding CCR4-NOT catalytic subunits, is preferentially expressed in mouse oocytes. Genetic deletion of Cnot6l impaired deadenylation and degradation of a subset of maternal mRNAs during oocyte maturation. Overtranslation of these undegraded mRNAs caused microtubule-chromosome organization defects, which led to activation of spindle assembly checkpoint and meiotic cell cycle arrest at prometaphase. Consequently, Cnot6l-/- female mice were severely subfertile. The function of CNOT6L in maturing oocytes is mediated by RNA-binding protein ZFP36L2, not maternal-to-zygotic transition licensing factor BTG4, which interacts with catalytic subunits CNOT7 and CNOT8 of CCR4-NOT Thus, recruitment of different adaptors by different catalytic subunits ensures stage-specific degradation of maternal mRNAs by CCR4-NOT This study provides the first direct genetic evidence that CCR4-NOT-dependent and particularly CNOT6L-dependent decay of selective maternal mRNAs is a prerequisite for meiotic maturation of oocytes.

Copper-Catalyzed Radical Cascade Cyclization To Access 3-Sulfonated Indenones with the AIE Phenomenon.

An efficient copper-catalyzed radical cascade cyclization strategy was developed, by which a wide variety of 3-sulfonyl substituted indenones were prepared in one pot via reaction of 2-alkynylbenzonitriles with sulfonyl hydrazides in the presence of TBHP and CuI under mild reaction conditions. Much more importantly, the 3-sulfonyl indenones, synthesized through our newly developed copper-catalyzed radical cascade cyclization strategy, were found to own typical aggregation-induced emission (AIE) properties, showing orange to red emission with large Stokes shift (more than 135 nm). In addition, such newly found AIEgens could be successfully used in live cell imaging, exhibiting excellent biocompatibility and application potential.

DCAF13 promotes pluripotency by negatively regulating SUV39H1 stability during early embryonic development.

Mammalian oocytes and zygotes have the unique ability to reprogram a somatic cell nucleus into a totipotent state. SUV39H1/2-mediated histone H3 lysine-9 trimethylation (H3K9me3) is a major barrier to efficient reprogramming. How SUV39H1/2 activities are regulated in early embryos and during generation of induced pluripotent stem cells (iPSCs) remains unclear. Since expression of the CRL4 E3 ubiquitin ligase in oocytes is crucial for female fertility, we analyzed putative CRL4 adaptors (DCAFs) and identified DCAF13 as a novel CRL4 adaptor that is essential for preimplantation embryonic development. Dcaf13 is expressed from eight-cell to morula stages in both murine and human embryos, and Dcaf13 knockout in mice causes preimplantation-stage mortality. Dcaf13 knockout embryos are arrested at the eight- to sixteen-cell stage before compaction, and this arrest is accompanied by high levels of H3K9me3. Mechanistically, CRL4-DCAF13 targets SUV39H1 for polyubiquitination and proteasomal degradation and therefore facilitates H3K9me3 removal and zygotic gene expression. Taken together, CRL4-DCAF13-mediated SUV39H1 degradation is an essential step for progressive genome reprogramming during preimplantation embryonic development.

Mitochondrial Function Regulated by Mitoguardin-1/2 Is Crucial for Ovarian Endocrine Functions and Ovulation.

The balances of mitochondrial dynamic changes, mitochondrial morphology, and mitochondrial number are critical in cell metabolism. Once they are disturbed, disorders in these processes generally cause diseases or even death in animals. We performed large-scale genetic screenings in fruit flies and discovered the mitoguardin gene (Miga) that encodes for a mitochondrial outer membrane protein. To examine the physiological functions of its mammalian homologs Miga1 and Miga2, we generated Miga1 and Miga2 single- and double-knockout mouse strains and found that the knockout mice were viable, but the females were subfertile. The ovarian phenotypes of these mice suggested that the MIGA1/2 proteins play an important role in ovulation and ovarian steroidogenesis. In vivo and in vitro analyses of Miga1/2-knockout granulosa cells showed severe defects in luteinization and steroidogenesis and disordered mitochondrial morphology and function in response to gonadotropins. This is a report of genes involved in mitochondrial fusion and morphology-regulating mitochondrial functions during ovulation and luteinization. These results suggest a mechanism of gonadotropin-regulated ovarian endocrine functions and provide clues for therapeutic treatments of infertile females.

The polycystic ovary syndrome-associated gene Yap1 is regulated by gonadotropins and sex steroid hormones in hyperandrogenism-induced oligo-ovulation in mouse.

STUDY QUESTION: What is the physiological function of Yes-associated protein-1 (Yap1), a susceptibility gene for polycystic ovary syndrome (PCOS), in ovarian granulosa cells (GCs)? SUMMARY ANSWER: Physiologically, steroid sex hormones stimulate follicle growth by activating YAP1; however, the preovulatory inhibition of YAP1 activity in GCs is a prerequisite of LH actions. WHAT IS KNOWN ALREADY: PCOS is a common gynecologic and endocrine disease with multiple short and long-term consequences. Many PCOS patients suffer anovulation caused by hyperandrogenism, but its etiology remains unclear. STUDY DESIGN, SIZE, DURATION: To study the effect of acute hyperandrogenism on ovulation, we injected pregnant mare serum gonadotrophin (PMSG)-primed (44 h) pubertal mice with dihydrotestosterone (DHT), the major biologically active form of androgen, in a superovulation assay. We investigated if YAP1 is regulated by testosterone and if it is potentially involved in follicle development and ovulation. Cultured primary GCs were subjected to Yap1 depletion by RNA interference and Yap1 overexpression by adenoviral infections. PARTICIPANTS/MATERIALS, SETTING, METHODS: Female mice at postnatal day (PD)-21~23 were analyzed to avoid the complexity of ovarian functions associated with estrous cycles and endogenous surges of gonadotropins. Immature mice were injected intraperitoneally with five IU PMSG to stimulate preovulatory follicle development followed 44 h later with five IU hCG to stimulate ovulation. For DHT treatments, female mice at PD23 were injected intraperitoneally with five IU PMSG followed 44 h later with five IU hCG alone (as control) or five IU hCG plus 100 µg DHT, which was dissolved in 0.1 ml DMSO. Methods of gene expression detection used include immunohistochemistry, immunofluorescence, Western blotting and quantitative PCR. More than three biological and technical replicates were included in each experiments. MAIN RESULTS AND THE ROLE OF CHANCE: we provide novel evidence in a mouse model that YAP1 is required for proliferation of ovarian GCs, but is down-regulated by LH through the extracellular-regulated kinase-1/2 (ERK1/2) cascade. Acute hyperandrogenism blocks LH actions and causes oligo-ovulation by activating YAP1. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Results shown were obtained only in mouse, and need to be further confirmed in human samples. WIDER IMPLICATIONS OF THE FINDINGS: These findings not only elucidated the role of YAP1 in maintaining normal ovarian functions, but also link the YAP1 deregulation to the pathogenesis of PCOS. STUDY FUNDING AND COMPETING INTEREST(S): This study is funded by the National Key Research and Development Program of China (2016YFC1000600 and 2017YFSF1001500) and National Natural Science Foundation of China (31528016, 31371449 and 31671558). The authors have no competing interests.