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Transgenerational increases in DNA methylation in Arabidopsis plants defective in active DNA demethylation.

Spontaneous gain or loss of DNA methylation occurs in plant and animal genomes, and DNA methylation changes can lead to meiotically stable epialleles that generate heritable phenotypic diversity. However, it is unclear whether transgenerational epigenetic stability may be regulated by any cellular factors. Here, we examined spontaneously occurring variations in DNA methylation in wild-type and ros1 mutant Arabidopsis plants that were propagated for ten generations from single-seed descent. We found that the ros1 mutant, which is defective in active DNA demethylation, showed an increased transgenerational epimutation rate. The ros1 mutation led to more spontaneously gained methylation than lost methylation at individual cytosines, compared to the wild type which had similar numbers of spontaneously gained and lost methylation cytosines. Consistently, transgenerational differentially methylated regions were also biased toward hypermethylation in the ros1 mutant. Our results reveal a genetic contribution of the ROS1 DNA demethylase to transgenerational epigenetic stability and suggest that ROS1 may have an unexpected surveillance function in preventing transgenerational DNA methylation increases.

Arabidopsis

YAP1 induces hepatocellular carcinoma via DNA demethylation rather than by canonical driver gene mutations.

Large-scale genome sequencing analyses have identified driver gene mutations (DGMs) in most cancers as well as their associated tumorigenic mechanisms. However, a small fraction of cancers are not positive for these canonical DGMs, leaving the mechanisms underpinning their formation a mystery. We hypothesized that canonical DGM-negative cancers might be driven by activation of the transcriptional coactivator YAP1 that led to the induction of epigenetic changes. To test this theory, we established a mouse mosaic model of hepatocellular carcinoma (HCC) in which we induced YAP1-TEAD activation in a few hepatocytes. Whole-exome sequencing did not identify canonical DGMs in HCCs, but bisulfite sequencing revealed widespread DNA demethylation leading to the transcriptional activation of multiple oncogenes. Knockdown of the DNA demethylation-promoting gene, Tet1, attenuated HCC formation in these mice. Single-cell spatial transcriptomics identified a Tet1-high subpopulation of HCC cells that interacted with other hepatic cell types. Our mechanistic mouse data align with the observation that YAP1-TEAD-TET1-associated signatures were also elevated in hepatocytes from patients with Fontan-associated liver disease (FALD), a condition associated with the development of HCCs with lower frequencies of canonical DGMs. Our study suggests that the YAP1-TEAD-TET1 axis promotes canonical DGM-negative HCC development, and provides new insights into the molecular processes involved.

Animals

Transposition element MERVL regulates DNA demethylation through TET3 in oxidative-damaged mouse preimplantation embryos.

Transposable elements (TEs) comprise approximately half of eukaryotic genomes and significantly contribute to genome plasticity. In this study, we focused on a specific TE, MERVL, which exhibits particular expression during the 2-cell stage and commonly serves as an indicator of embryonic totipotency. However, its precise role in embryo development remains mysterious. We utilized DRUG-seq to investigate the effects of oxidative damage on genes and TEs expression. Our findings revealed that exposure to hydrogen peroxide (H2O2) could induce DNA damage, apoptosis, and incomplete DNA demethylation in embryos, which were potentially associated with MERVL expression. To further explore its function, antisense nucleotides (ASO) targeting MERVL were constructed to knockdown the expression in early embryos. Notably, this knockdown led to the occurrence of DNA damage and apoptosis as early as the 2-cell stage, consequently reducing the number of embryos that could progress to the blastocyst stage. Moreover, we discovered that MERVL exerted an influence on the reprogramming of embryonic DNA methylation. In MERVL-deficient embryos, the activity of the DNA demethylase ten-eleven translocation 3 (TET3) was suppressed, resulting in impaired demethylation when compared to normal development. This impairment might underpin the mechanism that impacts embryonic development. Collectively, our study not only verified the crucial role of MERVL in embryonic development but also probed its regulatory function in DNA methylation reprogramming, thereby laying a solid foundation for further investigations into MERVL's role.

Animals

Maternal obesity in rats results in male-specific increases in genome-wide DNA methylation in postnatal offspring liver.

Male-specific peripubertal DNA demethylation in the liver has been reported in mice. Here, we investigated whether it also occurs in rats, the influence of maternal obesity and whether DNA demethylation changes contribute to observed sex-specific effects of maternal obesity in offspring. Female rats were fed a high-fat, high-sugar 'cafeteria' (Caf) diet before mating with standard chow-fed males. The offspring liver methylome and transcriptome were examined. Body weight was higher in Caf-fed dams prior to mating, during gestation and at parturition. Male and female offspring from Caf-fed dams had lower birth weights but higher adult weights and adiposity than offspring from chow-fed dams. A comparison of DNA methylation in 3-week-old weaner males versus female siblings from chow-fed dams did not reveal the male-specific DNA demethylation that was previously reported in mice. However, strong maternal diet effects in male weaner offspring methylation were observed. A comparison of female weaners from chow- versus Caf-fed dams showed a range of differences, with 39% of differentially methylated regions (DMRs) having higher methylation in Caf offspring and 61% of DMRs having higher methylation in chow offspring. In stark contrast, 99% of maternal-diet-induced DMRs in male weaner offspring had higher methylation in offspring from Caf-fed dams. This suggests that maternal obesity induces widespread hypermethylation in the male offspring liver at weaning. However, a comparison with RNA sequencing data revealed limited transcriptional changes at this developmental stage or in adult offspring. While these data highlight how environmentally sensitive DNA methylation is in the male rodent perinatal period, these methylation changes may not be a major contributor to sex differences in developmentally programmed liver disease.

Animals

Mutation in THO2, a component of THO/TREX complex, causes transcriptional gene silencing and genome-wide DNA methylation changes.

DNA methylation plays important roles in silencing of transgenes, endogenous genes, and transposable elements (TEs). To identify genes involved in antagonizing transcriptional or DNA hypermethylation-induced gene silencing, a genetic screening was conducted and thus a tho2-8 mutant was recovered. THO2 is a major component of the THO/TREX (Transcription-Export) complex, which plays essential roles in mRNA export. The tho2-8 mutation caused overaccumulation of DNA methylation on a d35S promoter ahead of LUC, suggesting its roles in antisilencing of transgenes. This mutation also resulted in significant genome-wide alterations in DNA methylation in a locus-specific manner, including 2513 hyper-DMRs and 1717 hypo-DMRs. The hyper-DMRs in the tho2-8 mutant not only exhibited a considerable overlap with those in DNA demethylation mutants (like ros1-7), but also with hypo-DMRs from nrpd1-3 and nrpe1-11 mutants, demonstrating that THO2 is able to protect those loci targeted by DNA demethylation and/or RdDM pathways from hypermethylation. The tho2-8 mutant also contained a plethora of CHH hypo-DMRs, which overlapped in large numbers with those from the nrpd1-3 and nrpe1-11 mutants, indicating that THO2 is required for the establishment/maintenance of DNA methylation at many loci. Additionally, the tho2-8 mutation caused an increase in overall 24-nt siRNA levels and many upregulated and downregulated DEGs/DETEs. The effects of THO2 on DNA methylation patterns appeared to be associated with the functioning of Pol IV and Pol V because THO2 physically interacted with NRPD7 and was necessary for normal accumulation levels of several Pol V-dependent IGNs' transcripts. Thus, this study provided valuable insights into new roles of THO2 in DNA methylation patterning.

DNA Methylation

Regulation of TET function by PROSER1 in development and hematologic malignancies.

Ten eleven translocation (TET) proteins are central regulators of DNA methylation homeostasis and play essential roles in development and disease, including hematopoietic malignancies. Among the three TET family members, mutations in TET2 are frequently observed in hematologic disorders. TET enzymes catalyze the iterative oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and further oxidized derivatives, enabling DNA demethylation. Beyond catalysis, TET proteins also perform important non-enzymatic functions mediated through interactions with diverse protein partners, highlighting the importance of defining their regulatory interactome. Previous studies identified several TET-associated factors, including O-Linked N-acetylglucosamine transferase (OGT), members of the Drosophila behavior/human splicing (DBHS) protein family, and proline and serine-rich protein 1 (PROSER1). However, these interactions were largely considered independently. Recent findings now demonstrate that TET proteins, OGT, PROSER1, and DBHS proteins assemble into a higher-order regulatory unit termed the TOPD (TET-OGT-PROSER1-DBHS) complex. In this review, we discuss how TOPD provides a conceptual framework for understanding multicomponent regulation of TET function, spatial control of DNA demethylation, and maintenance of epigenetic homeostasis, with implications for developmental syndromes and hematopoiesis.

Humans

Activity-dependent DNA methylation and demethylation: epigenetic regulators of learning and memory.

Learning and memory are fundamental cognitive processes that rely on activity-dependent epigenetic mechanisms to shape synaptic and neuronal plasticity. Among these, DNA methylation and demethylation have emerged as pivotal regulators that convert transient neural activity into enduring transcriptional programs. In mammals, DNA methylation marks include 5-methylcytosine (5mC) as well as the less well-established N6-methyladenine (6mA) and the more enigmatic N4-methylcytosine (4mC). Compared with 5mC, the abundance, genomic distribution, and regulatory role of 6mA and 4mC remain incompletely defined, partly due to low abundance and technical challenges, yet these non-canonical marks may provide an additional regulatory layer in specific biological contexts. Accordingly, this review focuses on the best-characterized pathway in the nervous system, 5mC and its activity-regulated oxidative turnover. This system comprises a dynamic spectrum of cytosine modifications, including 5mC, 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC), orchestrated by distinct enzyme families such as DNMTs, TETs, and TDG. We review current insights about how these regulators shape activity-induced gene expression programs underlying learning and memory, and we discuss how dysregulated DNA (de) methylation contributes to impaired transcriptional control and cognitive decline in neurodegenerative diseases, particularly Alzheimer's disease. Finally, we highlight recent advances in high-resolution mapping technologies for DNA modifications, which are expanding our ability to resolve cell type- and locus-specific epigenetic dynamics in the brain. A deeper understanding of these pathways may inform targeted strategies to preserve or restore cognitive function in neurological disorders.

Alzheimer’s disease

Identification of elements determining KIR gene demethylation at the CD56-bright stage of NK cell development.

The variegated expression of the KIR family of class I MHC receptors generates specialized natural killer (NK) cells capable of allele-specific HLA recognition. Understanding the mechanism of KIR gene activation will lead to improved methods for the generation of fully functional NK cells. A central RUNX-binding site in the KIR proximal promoter is required for gene activation. RUNX proteins recruit ten-eleven translocation (TET) proteins that generate 5-hydroxymethylcytosine (5hmC) and drive DNA demethylation. Assessment of 5-methylcytosine (5mC) and 5hmC residues at four stages of NK cell development reveals deposition of 5hmC primarily in a CREB site next to the RUNX site at the CD56Bright stage but not the subsequent CD56Dim stage representing fully mature NK cells. KIR promoter demethylation is delayed relative to other lineage-associated genes, indicating a high threshold for KIR gene demethylation in developing NK cells, and a window of opportunity for RUNX/TET-dependent KIR gene activation in CD56Bright NK cells.

6-base sequencing

FTDC1/2, oocyte-specific cofactors of DNMT1 required for epigenetic regulation and embryonic development.

The unique epigenetic patterns during gametogenesis and embryonic development indicate the existence of specialized methylation machinery. In the present study, we describe the discovery of two oocyte-specific cofactors of DNA methyltransferase 1 (DNMT1), encoded by uncharacterized genes, ferritin domain containing 1 and 2 (Ftdc1 and Ftdc2). Genetic ablation of Ftdc1 or Ftdc2 causes midgestation defects and female infertility. FTDC1 or FTDC2 depletion induces the progressive loss of DNA methylation including imprinted regions in early embryos. This loss correlates with a marked reduction in DNMT1 protein due to increased degradation, likely via the ubiquitin-proteasome pathway. Mechanistically, we find that FTDC1, FTDC2 and DNMT1 form a complex by direct interactions, thereby stabilizing each other. Surprisingly, knockout of Ftdc1 or Ftdc2 displayed stronger DNA demethylation phenotypes and earlier embryonic lethality than the Dnmt1-null mutant, implying their unique functions. These data suggest that FTDC1/2 are crucial players specifically involved in maintaining genomic methylation during embryogenesis, offering new insights into the epigenetic control of mammalian development.

DNA (Cytosine-5-)-Methyltransferase 1

Activation of the imprinted Prader-Willi syndrome locus by CRISPR-based epigenome editing.

Epigenome editing with DNA-targeting technologies such as CRISPR-dCas9 can be used to dissect gene regulatory mechanisms and potentially treat associated disorders. For example, Prader-Willi syndrome (PWS) results from loss of paternally expressed imprinted genes on chromosome 15q11.2-q13.3, although the maternal allele is intact but epigenetically silenced. Using CRISPR repression and activation screens in human induced pluripotent stem cells (iPSCs), we identified genomic elements that control the expression of the PWS gene SNRPN from the paternal and maternal chromosomes. We showed that either targeted transcriptional activation or DNA demethylation can activate the silenced maternal SNRPN and downstream PWS transcripts. However, these two approaches function at unique regions, preferentially activating different transcript variants and involving distinct epigenetic reprogramming mechanisms. Remarkably, transient expression of the targeted demethylase leads to stable, long-term maternal SNRPN expression in PWS iPSCs. This work uncovers targeted epigenetic manipulations to reprogram a disease-associated imprinted locus and suggests possible therapeutic interventions.

Prader-Willi Syndrome

Chronic psychological stress potentiates IgE class switch recombination via glucocorticoid receptor-mediated epigenetic reprogramming of B cells.

BACKGROUND: Chronic psychological stress is a well-recognized factor in the exacerbation of allergic diseases, with IgE playing a central role in their pathophysiology. However, the exact molecular mechanisms by which stress hormones directly influence IgE production and contribute to allergic responses remain largely uncharacterized. OBJECTIVE: This study aimed to elucidate the direct mechanisms through which chronic psychological stress, via elevated cortisol, regulates IgE class switch recombination (CSR) in B cells and contributes to stress-aggravated allergic inflammation in vivo. METHODS: We employed a chronic restraint stress (CRS) mouse model to investigate the impact of psychological stress on humoral immunity. In vitro experiments utilized primary murine B cells treated with physiological cortisol concentrations (250 nM), incorporating molecular techniques such as CRISPR-Cas9-mediated gene knockdown, chromatin immunoprecipitation (ChIP), whole-genome bisulfite sequencing, and pharmacological inhibitors of epigenetic enzymes. Primary human B cells and the U266 human myeloma cell line were used for translational validation. In vivo validation was performed using an ovalbumin (OVA)-induced allergic airway inflammation model with B cell-specific glucocorticoid receptor (GR) knockout mice. RESULTS: Chronic psychological stress significantly elevated plasma corticosterone and serum IgE levels in mice, with no changes in IgG1 or IgM. In purified in vitro B-cell cultures, cortisol promotes epigenetic remodeling at the Iε promoter region and enhances Iε germline transcript expression in an isotype-specific manner, and this effect was recapitulated in human B cells. GR bound to the Iε promoter's Amp_1 region (-154 to -62 bp), and CRISPR-Cas9-mediated GR knockdown abolished cortisol-induced IgE production. Mechanistically, cortisol increases enrichment of activating histone marks (H3K27ac, H3K4me3) and reduces H3K27me3 at the Iε promoter region, and induces site-specific DNA hypomethylation; inhibition of histone acetyltransferases (HATs) or DNA demethylation attenuated this effect. In vivo, B cell-specific GR knockout completely abrogated stress-induced exacerbation of allergic airway inflammation, including elevated serum IgE, eosinophilic inflammation, and airway hyperresponsiveness (AHR). CONCLUSION: Our findings support a mechanistic model in which chronic psychological stress, through elevated glucocorticoids, acts via GR to promote epigenetic remodeling at the Iε promoter region in B cells to enhance IgE synthesis and exacerbate allergic responses. This study provides a critical molecular link between the neuroendocrine system and adaptive immunity, offering promising therapeutic targets for stress-aggravated IgE-mediated diseases.

Animals

Telomere-to-telomere genome of Phoebe chekiangensis reveals that age-dependent CHG hypomethylation promotes floral transition via MADS-box gene activation.

Phoebe species are renowned for their highly valuable 'golden thread' timber; however, their protracted juvenile phase presents a significant obstacle to mechanistic investigations of floral induction. Phoebe chekiangensis, a rare early-flowering representative within this genus, provides a unique model system for dissecting the vegetative-to-reproductive phase transition. Nevertheless, the absence of a high-quality reference genome has severely hindered molecular insights into its developmental regulation. Here, we present the first telomere-to-telomere (T2T) genome assembly for P. chekiangensis, comprising two completely gap-free haplotypes with contig N50 values exceeding 65 Mb, base-level quality scores >36, and Long Terminal Repeat Assembly Index scores surpassing the gold standard threshold of 20. Approximately 29 000 genes were annotated per haplotype, supported by a BUSCO completeness score of >97%. Age-resolved transcriptomic landscapes identified two MADS-box transcription factors, PcMADS5 (AP1-like) and PcMADS19.1 (SOC1-like), as core activators of the floral transition. Both genes triggered precocious flowering when ectopically expressed in Arabidopsis thaliana. Whole-genome bisulfite sequencing revealed a progressive, age-dependent decline in CHG (where H is A, C, or T) DNA methylation, which was particularly pronounced at the PcMADS19.1 locus. Notably, DML1/2, which mediate active DNA demethylation, were coordinately upregulated during the onset of reproductive growth. Chemical demethylation using 5-azacytidine further diminished CHG methylation and selectively enhanced PcMADS19.1 expression, confirming a causal relationship between CHG hypomethylation and transcriptional activation. This work delivers the first chromosome-scale T2T genome within the genus Phoebe and uncovers CHG demethylation as a previously unrecognized epigenetic switch governing reproductive competence in woody perennials.

Journal Article

A probabilistic generative model for quantification of DNA modifications enables analysis of demethylation pathways.

We present a generative model, Lux, to quantify DNA methylation modifications from any combination of bisulfite sequencing approaches, including reduced, oxidative, TET-assisted, chemical-modification assisted, and methylase-assisted bisulfite sequencing data. Lux models all cytosine modifications (C, 5mC, 5hmC, 5fC, and 5caC) simultaneously together with experimental parameters, including bisulfite conversion and oxidation efficiencies, as well as various chemical labeling and protection steps. We show that Lux improves the quantification and comparison of cytosine modification levels and that Lux can process any oxidized methylcytosine sequencing data sets to quantify all cytosine modifications. Analysis of targeted data from Tet2-knockdown embryonic stem cells and T cells during development demonstrates DNA modification quantification at unprecedented detail, quantifies active demethylation pathways and reveals 5hmC localization in putative regulatory regions.

5-Methylcytosine

MDR1 DNA glycosylase regulates the expression of genomically imprinted genes and Helitrons.

Targeted demethylation by DNA glycosylases (DNGs) results in differential methylation between parental alleles in the endosperm, which drives imprinted expression. Here, we performed RNA sequencing on endosperm derived from DNG mutant mdr1 and wild-type (WT) endosperm. Consistent with the role of DNA methylation in gene silencing, we find 108 genes and 96 TEs differentially expressed (DE) transcripts that lost expression in the hypermethylated mdr1 mutant. Compared with other endosperm transcripts, the mdr1 targets are enriched for TEs (particularly Helitrons), and DE genes are depleted for both core genes and GO term assignments, suggesting that the majority of DE transcripts are TEs and pseudo-genes. By comparing DE genes to imprinting calls from prior studies, we find that the majority of DE genes have maternally biased expression, and approximately half of all maternally expressed genes (MEGs) are DE in this study. In contrast, no paternally expressed genes (PEGs) are DE. DNG-dependent imprinted genes are distinguished by maternal demethylation and expression primarily in the endosperm, so we also performed Enzymatic Methyl-seq on hybrids to identify maternal demethylation and utilized a W22 gene expression atlas to identify genes expressed primarily in the endosperm. Overall, approximately ⅔ of all MEGs show evidence of regulation by DNGs. Taken together, this study solidifies the role of MDR1 in the regulation of maternally expressed, imprinted genes and TEs and identifies subsets of genes with DNG-independent imprinting regulation.

Genomic Imprinting

Epigenetic priming and locus-specific demethylation enhance cell-death susceptibility in liver cancer.

Liver cancer treatment with epigenetic drugs remains challenging because demethylating agents such as 5-azacytidine (5-AZA) induce genome-wide toxicity and may activate oncogenes. We hypothesized that a low, nontoxic dose of 5-AZA could prime liver cancer cells by partially relaxing chromatin at selected loci to restore silenced cell-death regulators. HepG2 cells treated with 2 μM 5-AZA underwent ATAC-seq and RNA-seq to identify genes with promoter opening and increased expression. Among ten candidates, BFL-1 and SQOR were prioritized for roles in cell death and redox control. Forced expression of either gene increased sensitivity to TNF-α/cycloheximide (CHX) and sorafenib, both of which elevated mitochondrial reactive oxygen species. To establish causality in a physiological context, we used CRISPR-dCas9-TET1 to demethylate CpG-rich promoter regions of BFL-1 or SQOR. Locus-specific editing sensitized cells to TNF-α/CHX more rapidly than conventional overexpression and reproduced the heightened death response elicited by low-dose 5-AZA without baseline toxicity. Analysis of the cancer cell line encyclopedia and The Cancer Genome Atlas datasets showed consistent BFL-1 downregulation in liver cancer, variable SQOR expression across cancers, and positive correlations of both genes with tumor-suppression markers and immune-cell infiltration. These results indicate that targeted reactivation of BFL-1 and SQOR increases cell-death susceptibility in liver cancer cells. Integrating low-dose pharmacologic priming with precise epigenetic editing may preserve genome-wide methylation while restoring cell-death competence, providing proof-of-concept for locus-specific epigenetic therapy in liver cancer.

Humans

Screening and identification of the ncRNA-mRNA regulatory network associated with DNA methylation in goose embryonic myoblasts.

BACKGROUND: Local goose breeds Shitou and Wuzong exhibit distinct growth rates, implying divergent embryonic muscle development. This study used embryonic myoblasts from the Magang goose, an established model with superior growth traits, to explore the underlying common regulatory mechanisms. Extending our previous findings that 5-AZA (DNA methylation inhibitor) and BC339 (DNA hydroxylation inhibitor) oppositely affect myoblast proliferation and differentiation, we performed whole-transcriptome sequencing on inhibitor-treated goose embryonic myoblasts. This aimed to identify DNA methylation-mediated ncRNA-mRNA networks governing myoblast fate, with key interactions being functionally validated. RESULT: 5-AZA significantly promotes cell proliferation and differentiation by inhibiting DNA methyltransferase activity and reducing DNA methylation levels, whereas BC339 significantly suppresses cell proliferation and differentiation by inhibiting demethylation and increasing DNA methylation levels. Specifically, we identified 6,309 mRNAs, 579 lncRNAs, 194 miRNAs, and 825 circRNAs that were differentially expressed in response to 5-AZA and BC339 treatment. Based on GO and KEGG enrichment analyses, differentially expressed genes related to muscle development were selected to construct a ceRNA network. This network comprises 5 differentially expressed lncRNAs (DELs: MSTRG.17572.1, XR_001211738.1, MSTRG.1886.1, XR_001212555.1, MSTRG.8995.2), 2 differentially expressed circRNAs (DECs: novel_circ_029953, novel_circ_017636), 11 differentially expressed miRNAs (DEMs: miR-383-x, miR-10174-y, miR-191-x, miR-24-x, miR-9619-y, novel-m0303-5p, novel-m0105-3p, miR-204-x, miR-211-z, novel-m0075, miR-26-y), 5 differentially expressed genes (DEGs: KIF3A, CCND1, PPM1A, Table 2, TGFBR1), forming a total of 24 interactions. This study identified miR-9619-y as a critical negative regulator of goose embryonic myoblast development through targeted inhibition of CCND1. Dual-luciferase reporter assays confirmed the direct binding of miR-9619-y to the 3'-untranslated region of CCND1. Functional experiments demonstrated that overexpression of miR-9619-y significantly reduced the EdU-positive cell ratio and myotube area percentage, accompanied by cell cycle arrest at the G0/G1 phase. Conversely, inhibition of miR-9619-y promoted myoblast proliferation and differentiation while decreasing the proportion of cells in G0/G1 phase. During the proliferation stage, miR-9619-y overexpression significantly suppressed CCND1 expression at both mRNA and protein levels, down-regulated MyoD expression, and reduced Myf5 mRNA abundance; whereas miR-9619-y inhibition up-regulated these genes and their corresponding proteins. During the differentiation stage, overexpression of miR-9619-y similarly decreased the mRNA levels of CCND1, Myh1, and MyoG, as well as the protein levels of MyHC and CCND1, with inhibition producing the opposite effects. CONCLUSION: In this study, we predicted a ceRNA network based on bioinformatics analysis governing goose embryonic myoblast development, identifying key molecular components including mRNAs, miRNAs, lncRNAs, and circRNAs, along with 24 regulatory axes. Functional experiments further demonstrated that miR-9619-y arrests cell cycle progression and negatively regulates the proliferation and differentiation of goose embryonic myoblasts, as evidenced by its impact on both the mRNA and protein expression of key myogenic factors through targeted inhibition of CCND1. These findings, together with the bioinformatically predicted ceRNA network, suggest potential complex post-transcriptional regulatory mechanisms underlying myogenesis in geese and offer candidate molecular targets for genetic improvement of meat production performance in waterfowl breeding programs.

Animals

OsCLSY4 modulates epigenomic patterns and grain size in rice.

De novo DNA methylation, orchestrated by the RNA-directed DNA methylation (RdDM) pathway, is essential for gene regulation and transposon silencing. While CLASSY (CLSY) proteins facilitate RNA POLYMERASE IV (Pol IV) recruitment to initiate the RdDM pathway in plants, their roles in crops are incompletely explored. Here, we report OsCLSY4 as the dominant regulator within the OsCLSY family, driving Pol IV-mediated epigenomic patterns and influencing diverse agricultural traits. Epigenomics analyses reveal that OsCLSY4 controls over 95% of Pol IV-dependent 24-nucleotide small interfering RNA (24-nt siRNA) clusters and more than 70% of Pol IV-dependent hypomethylated CHH differentially methylated regions (DMRs), predominantly at miniature inverted-repeat transposable elements (MITEs). Loss of OsCLSY4 leads to dysregulation of MADS22 and GA20ox1 in a DNA methylation-dependent manner. SunTag-mediated targeted demethylation confirms that reduced DNA methylation in promoter regions leads to MADS22 activation and GA20ox1 repression to influence grain size, linking epigenetic changes to phenotypic outcomes of osclsy4. Moreover, OsCLSY4 governs tissue-specific methylation patterns in panicle and seedling. Mechanistically, OsCLSY4 is the predominantly expressed OsCLSY family member and interacts with Pol IV. Collectively, our findings position OsCLSY4 as a central hub for Pol IV-mediated epigenomic regulation in rice and suggest its potential utility in epigenetic breeding strategies.

Oryza

Inhibition of dimethylnitrosamine-induced strand breaks in liver DNA and liver cell necrosis by diethyldithiocarbamate.

Diethyldithiocarbamate (DEDTC) prevented dimethylnitrosamine (DMN)-induced strand breaks in liver DNA and liver cell necrosis in male Wistar rats. In contrast, DEDTC did not inhibit the fragmentation of liver DNA caused by several other chemical carcinogens (N-hydroxy-2-acetylaminofluorene, 3-hydroxyxanthine, aflatoxin B1, N-acetoxy-2-acetylaminofluorene, methyl methanesulfonate, methylnitrosourea, and methylazoxy-methanol acetate), whether or not they required metabolic activation. Aminoacetonitrile exerted an action similar to that of DEDTC. The inhibitory effect was transitory, lasting at least for 4 hours, and protection for longer than 4 hours required multiple administrations of DEDTC. DEDTC also inhibited the serum clearance of DMN, methylation of liver DNA, and oxidative demethylation of DMN in the in vitro hepatic microsomal system prepared from either male Wistar rats or from hamsters. Interference of the metabolism of DMN appeared to be the mechanism by which DEDTC arrested DMN-induced biochemical and biologic effects.

Aminoacetonitrile