Endoscopic ultrasonography-related diagnostic accuracy and clinical significance on small rectal neuroendocrine neoplasms.

This research aimed to examine the diagnostic accuracy and clinical significance of endoscopic ultrasonography (EUS) in the context of small rectal neuroendocrine neoplasms (NENs). A total of 108 patients with rectal subepithelial lesions (SELs) with a diameter of < 20 mm were included in the analysis. The diagnosis and depth assessment of EUS was compared to the histology findings. The prevalence of NENs in rectal SELs was 78.7% (85/108). The sensitivity of EUS in detecting rectal NENs was 98.9% (84/85), while the specificity was 52.2% (12/23). Overall, the diagnostic accuracy of EUS in identifying rectal NENs was 88.9% (96/108). The overall accuracy rate for EUS in assessing the depth of invasion in rectal NENs was 92.9% (78/84). Therefore, EUS demonstrates reasonable diagnostic accuracy in detecting small rectal NENs, with good sensitivity but inferior specificity. EUS may also assist physicians in assessing the depth of invasion in small rectal NENs before endoscopic excision.

Auto-suppression of Tet dioxygenases protects the mouse oocyte genome from oxidative demethylation.

DNA cytosine methylation plays a vital role in repressing retrotransposons, and such derepression is linked with developmental failure, tumorigenesis and aging. DNA methylation patterns are formed by precisely regulated actions of DNA methylation writers (DNA methyltransferases) and erasers (TET, ten-eleven translocation dioxygenases). However, the mechanisms underlying target-specific oxidation of 5mC by TET dioxygenases remain largely unexplored. Here we show that a large low-complexity domain (LCD), located in the catalytic part of Tet enzymes, negatively regulates the dioxygenase activity. Recombinant Tet3 lacking LCD is shown to be hyperactive in converting 5mC into oxidized species in vitro. Endogenous expression of the hyperactive Tet3 mutant in mouse oocytes results in genome-wide 5mC oxidation. Notably, the occurrence of aberrant 5mC oxidation correlates with a consequent loss of the repressive histone mark H3K9me3 at ERVK retrotransposons. The erosion of both 5mC and H3K9me3 causes ERVK derepression along with upregulation of their neighboring genes, potentially leading to the impairment of oocyte development. These findings suggest that Tet dioxygenases use an intrinsic auto-regulatory mechanism to tightly regulate their enzymatic activity, thus achieving spatiotemporal specificity of methylome reprogramming, and highlight the importance of methylome integrity for development.

[Metabolomic study on urine of chronic inflammation rats treated with Buyang Huanwu Decoction based on UPLC-Q-TOF-MS].

The study investigated the effect of Buyang Huanwu Decoction(BYHWD) on endogenous biomarkers in the urine of rats with chronic inflammation induced by lipopolysaccharide(LPS) using ultra-high performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry(UPLC-Q-TOF-MS), aiming to elucidate the molecular mechanism underlying the therapeutic effect of BYHWD on chronic inflammation from a metabolomics perspective. Male SD rats were randomly divided into a normal group, a model group, and low-, medium-, and high-dose BYHWD groups(7.5, 15, and 30 g·kg~(-1)). The model group and BYHWD groups received tail intravenous injection of LPS(200 µg·kg~(-1)) on the first day of each week, followed by oral administration of BYHWD once a day for four consecutive weeks. Urine samples were collected at the end of the administration period, and UPLC-Q-TOF-MS was used to analyze the metabolic profiles of the rat urine in each group. Multivariate statistical analysis methods such as principal component analysis(PCA), partial least squares-discriminant analysis(PLS-DA), and orthogonal partial least squares-discriminant analysis(OPLS-DA) were used to analyze the effect of BYHWD on endogenous metabolites. One-way ANOVA and variable importance for the projection(VIP) were used to screen for potential biomarkers related to chronic inflammation. The identified biomarkers were subjected to pathway and enrichment analysis using MetaboAnalyst 5.0. A total of 25 potential biomarkers were screened and identified in the rat urine in this experiment. Compared with the normal group, the model group showed significant increases in the levels of 14 substances(P<0.05) and significant decreases in the levels of 11 substances(P<0.05). BYHWD was able to effectively reverse the trend of most endogenous biomarkers. Compared with the model group, BYHWD significantly down-regulated 13 biomarkers(P<0.05) and up-regulated 10 biomarkers(P<0.05). The metabolic products were mainly related to the biosynthesis of pantothenic acid and coenzyme A, tryptophan metabolism, retinol metabolism, and propionate metabolism. BYHWD has therapeutic effect on chronic inflammation induced by LPS, which may be related to its ability to improve the levels of endogenous metabolites, enhance the body's anti-inflammatory and antioxidant capabilities, and restore normal metabolic activity.

STING activation in TET2-mutated hematopoietic stem/progenitor cells contributes to the increased self-renewal and neoplastic transformation.

Somatic loss-of-function mutations of the dioxygenase Ten-eleven translocation-2 (TET2) occur frequently in individuals with clonal hematopoiesis (CH) and acute myeloid leukemia (AML). These common hematopoietic disorders can be recapitulated in mouse models. However, the underlying mechanisms by which the deficiency in TET2 promotes these disorders remain unclear. Here we show that the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway is activated to mediate the effect of TET2 deficiency in dysregulated hematopoiesis in mouse models. DNA damage arising in Tet2-deficient hematopoietic stem/progenitor cells (HSPCs) leads to activation of the cGAS-STING pathway which in turn promotes the enhanced self-renewal and development of CH. Notably, both pharmacological inhibition and genetic deletion of STING suppresses Tet2 mutation-induced aberrant hematopoiesis. In patient-derived xenograft (PDX) models, STING inhibition specifically attenuates the proliferation of leukemia cells from TET2-mutated individuals. These observations suggest that the development of CH associated with TET2 mutations is powered through chronic inflammation dependent on the activated cGAS-STING pathway and that STING may represent a potential target for intervention of relevant hematopoietic diseases.

Vaccinia virus induces EMT-like transformation and RhoA-mediated mesenchymal migration.

The emerging outbreak of monkeypox is closely associated with the viral infection and spreading, threatening global public health. Virus-induced cell migration facilitates viral transmission. However, the mechanism underlying this type of cell migration remains unclear. Here we investigate the motility of cells infected by vaccinia virus (VACV), a close relative of monkeypox, through combining multi-omics analyses and high-resolution live-cell imaging. We find that, upon VACV infection, the epithelial cells undergo epithelial-mesenchymal transition-like transformation, during which they lose intercellular junctions and acquire the migratory capacity to promote viral spreading. After transformation, VACV-hijacked RhoA signaling significantly alters cellular morphology and rearranges the actin cytoskeleton involving the depolymerization of robust actin stress fibers, leading-edge protrusion formation, and the rear-edge recontraction, which coordinates VACV-induced cell migration. Our study reveals how poxviruses alter the epithelial phenotype and regulate RhoA signaling to induce fast migration, providing a unique perspective to understand the pathogenesis of poxviruses.

Efficient methods for multiple types of precise gene-editing in Chlamydomonas.

Precise gene-editing using CRISPR/Cas9 technology remains a long-standing challenge, especially for genes with low expression and no selectable phenotypes in Chlamydomonas reinhardtii, a classic model for photosynthesis and cilia research. Here, we developed a multi-type and precise genetic manipulation method in which a DNA break was generated by Cas9 nuclease and the repair was mediated using a homologous DNA template. The efficacy of this method was demonstrated for several types of gene editing, including inactivation of two low-expression genes (CrTET1 and CrKU80), the introduction of a FLAG-HA epitope tag into VIPP1, IFT46, CrTET1 and CrKU80 genes, and placing a YFP tag into VIPP1 and IFT46 for live-cell imaging. We also successfully performed a single amino acid substitution for the FLA3, FLA10 and FTSY genes, and documented the attainment of the anticipated phenotypes. Lastly, we demonstrated that precise fragment deletion from the 3'-UTR of MAA7 and VIPP1 resulted in a stable knock-down effect. Overall, our study has established efficient methods for multiple types of precise gene editing in Chlamydomonas, enabling substitution, insertion and deletion at the base resolution, thus improving the potential of this alga in both basic research and industrial applications.

Primulinajiulianshanensis, a new species of Gesneriaceae from Jiangxi Province, China.

Primulinajiulianshanensis F.Wen & G.L.Xu, a new species of Gesneriaceae from Jiulianshan National Nature Reserve of Jiangxi Province, China, is described and illustrated here. Molecular evidence showed it was sister to P.wenii Jian Li & L.J.Yan, while the morphological observation found clear differences between them, petiole, both sides of leaf blades, adaxial surface of the calyx lobes, corolla inside toward the bottom, bract margins covered glandular-pubescent hairs in P.jiulianshanensis (vs. no glandular-pubescent hairs in P.wenii); lateral bracts 4-9 × ca. 2 mm, the central one 2-5 × 1-1.5 mm, adaxially glabrous but sparsely pubescent at apex (vs. lateral bracts 14-16 × 2.5-3.0 mm, the central one 10-12 × 1.3-1.6 mm, all adaxially pubescent); calyx lobes 8-11 × ca. 2 mm, each side with several brown serrate teeth at apex (vs. 14-15 × ca. 2.5 mm, margin entire); filaments and staminodes sparsely yellow glandular-puberulent (vs. white, glabrous).

Base editing-mediated one-step inactivation of the Dnmt gene family reveals critical roles of DNA methylation during mouse gastrulation.

During embryo development, DNA methylation is established by DNMT3A/3B and subsequently maintained by DNMT1. While much research has been done in this field, the functional significance of DNA methylation in embryogenesis remains unknown. Here, we establish a system of simultaneous inactivation of multiple endogenous genes in zygotes through screening for base editors that can efficiently introduce a stop codon. Embryos with mutations in Dnmts and/or Tets can be generated in one step with IMGZ. Dnmt-null embryos display gastrulation failure at E7.5. Interestingly, although DNA methylation is absent, gastrulation-related pathways are down-regulated in Dnmt-null embryos. Moreover, DNMT1, DNMT3A, and DNMT3B are critical for gastrulation, and their functions are independent of TET proteins. Hypermethylation can be sustained by either DNMT1 or DNMT3A/3B at some promoters, which are related to the suppression of miRNAs. The introduction of a single mutant allele of six miRNAs and paternal IG-DMR partially restores primitive streak elongation in Dnmt-null embryos. Thus, our results unveil an epigenetic correlation between promoter methylation and suppression of miRNA expression for gastrulation and demonstrate that IMGZ can accelerate deciphering the functions of multiple genes in vivo.

DNA dioxygenases Tet2/3 regulate gene promoter accessibility and chromatin topology in lineage-specific loci to control epithelial differentiation.

Execution of lineage-specific differentiation programs requires tight coordination between many regulators including Ten-eleven translocation (TET) family enzymes, catalyzing 5-methylcytosine oxidation in DNA. Here, by using Keratin 14-Cre-driven ablation of Tet genes in skin epithelial cells, we demonstrate that ablation of Tet2/Tet3 results in marked alterations of hair shape and length followed by hair loss. We show that, through DNA demethylation, Tet2/Tet3 control chromatin accessibility and Dlx3 binding and promoter activity of the Krt25 and Krt28 genes regulating hair shape, as well as regulate interactions between the Krt28 gene promoter and distal enhancer. Moreover, Tet2/Tet3 also control three-dimensional chromatin topology in Keratin type I/II gene loci via DNA methylation-independent mechanisms. These data demonstrate the essential roles for Tet2/3 in establishment of lineage-specific gene expression program and control of Dlx3/Krt25/Krt28 axis in hair follicle epithelial cells and implicate modulation of DNA methylation as a novel approach for hair growth control.

DNA methyltransferases are complementary in maintaining DNA methylation in embryonic stem cells.

ZFP57 and ZFP445 maintain genomic imprinting in mouse embryos. We found DNA methylation was lost at most examined imprinting control regions (ICRs) in mouse Zfp57 mutant ES cells, which could not be prevented by the elimination of three TET proteins. To elucidate methylation maintenance mechanisms, we generated mutant ES clones lacking three major DNA methyltransferases (DNMTs). Intriguingly, DNMT3A and DNMT3B were essential for DNA methylation at a subset of ICRs in mouse ES cells although DNMT1 maintained DNA methylation at most known ICRs. These were similarly observed after extended culture. Germline-derived DNA methylation was lost at the examined ICRs lacking DNMTs according to allelic analysis. Similar to DNMT1, DNMT3A and DNMT3B were required for maintaining DNA methylation at repeats, genic regions, and other genomic sequences. Therefore, three DNA methyltransferases play complementary roles in maintaining DNA methylation in mouse ES cells including DNA methylation at the ICRs primarily mediated through the ZFP57-dependent pathway.

Targeted demethylation at ZNF154 promotor upregulates ZNF154 expression and inhibits the proliferation and migration of Esophageal Squamous Carcinoma cells.

Zinc finger protein 154 (ZNF154) is hypermethylated at the promoter in many epithelial-derived solid tumors. However, its methylation status and function in esophageal squamous carcinoma (ESCC) are poorly understood. We found that the ZNF154 promoter is hypermethylated in ESCC and portends poor prognosis. In addition, ZNF154 functions as a tumor suppressor gene (TSG) in ESCC, and is downregulated by promoter hypermethylation. We established a targeted demethylation strategy based on CRISPR/dCas9 technology and found that the hypermethylation of ZNF154 promoter repressed ZNF154 induction, which in turn promoted the proliferation and migration of ESCC cells in vitro and in vivo. Finally, high-throughput CUT&Tag analysis, GEPIA software and qPCR were used to revealed the role of ZNF154 as a transcription factor to upregulate the expression of ESCC-associated tumor suppressor genes. Taken together, hypermethylation of the ZNF154 promoter plays an important role in the development of ESCC, and epigenetic editing is a promising tool for inhibiting ESCC cells with aberrant DNA methylation.

TET enzymes regulate skeletal development through increasing chromatin accessibility of RUNX2 target genes.

The Ten-eleven translocation (TET) family of dioxygenases mediate cytosine demethylation by catalyzing the oxidation of 5-methylcytosine (5mC). TET-mediated DNA demethylation controls the proper differentiation of embryonic stem cells and TET members display functional redundancy during early gastrulation. However, it is unclear if TET proteins have functional significance in mammalian skeletal development. Here, we report that Tet genes deficiency in mesoderm mesenchymal stem cells results in severe defects of bone development. The existence of any single Tet gene allele can support early bone formation, suggesting a functional redundancy of TET proteins. Integrative analyses of RNA-seq, Whole Genome Bisulfite Sequencing (WGBS), 5hmC-Seal and Assay for Transposase-Accessible Chromatin (ATAC-seq) demonstrate that TET-mediated demethylation increases the chromatin accessibility of target genes by RUNX2 and facilities RUNX2-regulated transcription. In addition, TET proteins interact with RUNX2 through their catalytic domain to regulate cytosine methylation around RUNX2 binding region. The catalytic domain is indispensable for TET enzymes to regulate RUNX2 transcription activity on its target genes and to regulate bone development. These results demonstrate that TET enzymes function to regulate RUNX2 activity and maintain skeletal homeostasis.

[Effect of Gegen Qinlian Decoction on methylation and expression of Scd1gene in adipose tissue of insulin resistant rats and correlations between methylation and physiological and biochemical parameters].

This study aimed to explore the effect of Gegen Qinlian Decoction(GQD) on the methylation and mRNA expression level of stearoyl CoA desaturase(SCD) gene in the adipose tissue of rats with insulin resistance(IR) induced by high-fat diet as well as the correlations between methylation and physiological and biochemical indicators. The animals were divided into seven groups, namely, blank control(C) group, IR model group, low-(1.65 g·kg~(-1)), medium-(4.95 g·kg~(-1)), and high(14.85 g·kg~(-1))-dose GQD(GQDL, GQDM, and GQDH) groups, rosiglitazone(RGN, 5 mg·kg~(-1)) group, and simvastatin(SVT, 10 mg·kg~(-1)) group. The rat epididymal adipose tissue was collected for detecting all the cytosine methylation levels in two fragments of Scd1 gene by bisulfite sequencing PCR(BSP). Scd1-1 was located in CG shores and Scd1-2 in CG islands, including the transcriptional start site(TSS). The Scd1 mRNA level was determined by quantitative real-time PCR(q-PCR). Spearman correlation coefficient was used to analyze the correlations between amplified fragment C methylation and physiological and biochemical indicators. The results showed that GQDM remarkably reversed the elevated CG7 methylation in the TSS upstream region of Scd1-2 triggered by high-fat diet. GQDL significantly reversed the lowered total CG methylation in the downstream region of Scd1-2 induced by the high-fat diet. GQD did not significantly improve the decreased Scd1 mRNA expression caused by high-fat diet. Changes in methylation of the total CG, CG5 and CT11 of Scd1-1 in CG shores exhibited significant negative correlations with the serum triglyceride(TG) but positive correlation with the Scd1 mRNA level. The methylation of several C sites in the TSS upstream region of Scd1-2 was positively correlated with physiological and biochemical parameters. The methylation of several CG sites in the TSS downstream region of Scd1-2 was negatively associated with physiological and biochemical parameters. Besides, the methylation of several CH sites in the downstream fragment was positively correlated with physiological and biochemical parameters. All these have demonstrated that GQD may exert the therapeutic effect by regulating the methylation of CG7 in the TSS upstream region and total CG site in the TSS downstream region of Scd1 gene. The methylation of total CG, CG5 and CT11 sites in CG shores of Scd1 gene may be important targets for regulating Scd1 mRNA level and affecting serum TG.

Maternal inheritance of glucose intolerance via oocyte TET3 insufficiency.

Diabetes mellitus is prevalent among women of reproductive age, and many women are left undiagnosed or untreated1. Gestational diabetes has profound and enduring effects on the long-term health of the offspring2,3. However, the link between pregestational diabetes and disease risk into adulthood in the next generation has not been sufficiently investigated. Here we show that pregestational hyperglycaemia renders the offspring more vulnerable to glucose intolerance. The expression of TET3 dioxygenase, responsible for 5-methylcytosine oxidation and DNA demethylation in the zygote4, is reduced in oocytes from a mouse model of hyperglycaemia (HG mice) and humans with diabetes. Insufficient demethylation by oocyte TET3 contributes to hypermethylation at the paternal alleles of several insulin secretion genes, including the glucokinase gene (Gck), that persists from zygote to adult, promoting impaired glucose homeostasis largely owing to the defect in glucose-stimulated insulin secretion. Consistent with these findings, mouse progenies derived from the oocytes of maternal heterozygous and homozygous Tet3 deletion display glucose intolerance and epigenetic abnormalities similar to those from the oocytes of HG mice. Moreover, the expression of exogenous Tet3 mRNA in oocytes from HG mice ameliorates the maternal effect in offspring. Thus, our observations suggest an environment-sensitive window in oocyte development that confers predisposition to glucose intolerance in the next generation through TET3 insufficiency rather than through a direct perturbation of the oocyte epigenome. This finding suggests a potential benefit of pre-conception interventions in mothers to protect the health of offspring.

Loss of TET reprograms Wnt signaling through impaired demethylation to promote lung cancer development.

Oncogenic imbalance of DNA methylation is well recognized in cancer development. The ten-eleven translocation (TET) family of dioxygenases, which facilitates DNA demethylation, is frequently dysregulated in cancers. How such dysregulation contributes to tumorigenesis remains poorly understood, especially in solid tumors which present infrequent mutational incidence of TET genes. Here, we identify loss-of-function mutations of TET in 7.4% of human lung adenocarcinoma (LUAD), which frequently co-occur with oncogenic KRAS mutations, and this co-occurrence is predictive of poor survival in LUAD patients. Using an autochthonous mouse model of KrasG12D -driven LUAD, we show that individual or combinational loss of Tet genes markedly promotes tumor development. In this Kras-mutant and Tet-deficient model, the premalignant lung epithelium undergoes neoplastic reprogramming of DNA methylation and transcription, with a particular impact on Wnt signaling. Among the Wnt-associated components that undergo reprogramming, multiple canonical Wnt antagonizing genes present impaired expression arising from elevated DNA methylation, triggering aberrant activation of Wnt signaling. These impairments can be largely reversed upon the restoration of TET activity. Correspondingly, genetic depletion of ß-catenin, the transcriptional effector of Wnt signaling, substantially reverts the malignant progression of Tet-deficient LUAD. These findings reveal TET enzymes as critical epigenetic barriers against lung tumorigenesis and highlight the therapeutic vulnerability of TET-mutant lung cancer through targeting Wnt signaling.

Molecular, chromosomal, and morphological evidence reveals a new allotetraploid fern species of Asplenium (Aspleniaceae) from southern Jiangxi, China.

Aspleniumjiulianshanense, a new tetraploid fern species of the A.normale complex (Aspleniaceae) from Jiulianshan National Nature Reserve, southern Jiangxi, China is described and illustrated. We inferred the phylogenetic position of the new species based on sequences from seven plastid markers (atpB, rbcL, rps4, rps4-trnS, trnL, trnL-F, and trnG) and one low-copy nuclear gene, pgiC. The plastid phylogeny supported a close relationship among the new species A.jiulianshanense, A.minutifolium, and A.kiangsuense, while the nuclear phylogeny differed in topology from the plastid tree. The new species may be due to hybridization between A.kiangsuense and A.boreale. Morphologically, the new species can easily be distinguished from other members of the A.normale complex by rachises bearing a gemma near the apex, pinna margins entire to sparsely crenate, and (1‒)3‒4(‒6) sori per pinna.

Genome-wide analysis of 8-oxo-7,8-dihydro-2'-deoxyguanosine at single-nucleotide resolution unveils reduced occurrence of oxidative damage at G-quadruplex sites.

8-Oxo-7,8-dihydro-2'-deoxyguanosine (OG), one of the most common oxidative DNA damages, causes genome instability and is associated with cancer, neurological diseases and aging. In addition, OG and its repair intermediates can regulate gene transcription, and thus play a role in sensing cellular oxidative stress. However, the lack of methods to precisely map OG has hindered the study of its biological roles. Here, we developed a single-nucleotide resolution OG-sequencing method, named CLAPS-seq (Chemical Labeling And Polymerase Stalling Sequencing), to measure the genome-wide distribution of both exogenous and endogenous OGs with high specificity. Our data identified decreased OG occurrence at G-quadruplexes (G4s), in association with underrepresentation of OGs in promoters which have high GC content. Furthermore, we discovered that potential quadruplex sequences (PQSs) were hotspots of OGs, implying a role of non-G4-PQSs in OG-mediated oxidative stress response.

Loss of ten-eleven translocation 2 induces cardiac hypertrophy and fibrosis through modulating ERK signaling pathway.

The ten-eleven translocation (Tet) family of dioxygenases convert 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). Previous studies have shown that 5hmC-mediated epigenetic modifications play essential roles in diverse biological processes and diseases. Here, we show that Tet proteins and 5hmC display dynamic features during postnatal cardiac development and that Tet2 is the predominant dioxygenase present in heart. Tet2 knockout results in abnormal cardiac function, progressive cardiac hypertrophy and fibrosis. Mechanistically, Tet2 deficiency leads to reduced hydroxymethylation in the cardiac genome and alters the cardiac transcriptome. Mechanistically, Tet2 loss leads to a decrease of Hspa1b expression, a regulator of the extracellular signal-regulated protein kinase (Erk) signaling pathway, which leads to over-activation of Erk signaling. Acute Hspa1b knock down (KD) increased the phosphorylation of Erk and induced hypertrophy of cardiomyocytes, which could be blocked by Erk signaling inhibitor. Consistently, ectopic expression of Hspa1b was able to rescue the deficits of cardiomyocytes induced by Tet2 depletion. Taken together, our study's results reveal the important roles of Tet2-mediated DNA hydroxymethylation in cardiac development and function.

Tet1 Deficiency Leads to Premature Ovarian Failure.

Tet enzymes participate in DNA demethylation and play critical roles in stem cell pluripotency and differentiation. DNA methylation alters with age. We find that Tet1 deficiency reduces fertility and leads to accelerated reproductive failure with age. Noticeably, Tet1-deficient mice at young age exhibit dramatically reduced follicle reserve and the follicle reserve further decreases with age, phenomenon consistent with premature ovarian failure (POF) syndrome. Consequently, Tet1-deficient mice become infertile by reproductive middle age, while age matched wild-type mice still robustly reproduce. Moreover, by single cell transcriptome analysis of oocytes, Tet1 deficiency elevates organelle fission, associated with defects in ubiquitination and declined autophagy, and also upregulates signaling pathways for Alzheimer's diseases, but down-regulates X-chromosome linked genes, such as Fmr1, which is known to be implicated in POF. Additionally, Line1 is aberrantly upregulated and endogenous retroviruses also are altered in Tet1-deficient oocytes. These molecular changes are consistent with oocyte senescence and follicle atresia and depletion found in premature ovarian failure or insufficiency. Our data suggest that Tet1 enzyme plays roles in maintaining oocyte quality as well as oocyte number and follicle reserve and its deficiency can lead to POF.