N⁶-methyladenosine (m⁶A) modification plays a critical role in cell cycle regulation, while the mechanism of m⁶A in regulating mitosis remains underexplored. Here, we found that the total m⁶A modification level in cells increased during mitosis by the liquid chromatography-mass spectrometry/mass spectrometry and m⁶A dot blot assays. Silencing methyltransferase-like 3 (METTL3) or METTL14 results in delayed mitosis, abnormal spindle assembly, and chromosome segregation defects by the immunofluorescence. By analyzing transcriptome-wide m⁶A targets in HeLa cells, we identified polo-like kinase 1 (PLK1) as a key gene modified by m⁶A in regulating mitosis. Specifically, through immunoblotting and RNA pulldown, m⁶A modification inhibits PLK1 translation via YTH N⁶-methyladenosine RNA binding protein 1, thus mediating cell cycle homeostasis. Demethylation of PLK1 mRNA leads to significant mitotic abnormalities. These findings highlight the critical role of m⁶A in regulating mitosis and the potential of m⁶A as a therapeutic target in proliferative diseases such as cancer.
Humans ; Polo-Like Kinase 1 ; Cell Cycle Proteins/metabolism* ; Proto-Oncogene Proteins/metabolism* ; Protein Serine-Threonine Kinases/metabolism* ; Mitosis/physiology* ; HeLa Cells ; Adenosine/genetics* ; Methyltransferases/metabolism* ; RNA, Messenger/metabolism* ; RNA-Binding Proteins/metabolism*

Geminiviruses cause substantial crop yield losses worldwide. The replication initiator protein (Rep) encoded by geminiviruses is indispensable for geminiviral replication. The Rep protein encoded by beet severe curly top virus (BSCTV, genus Curtovirus, family Geminiviridae) induces VARIANT IN METHYLATION 5 (VIM5) expression in Arabidopsis leaves upon BSCTV infection. VIM5 functions as a ubiquitination-related E3 ligase to promote the proteasomal degradation of methyltransferases, resulting in reduction of methylation levels in the BSCTV C2-3 promoter. However, the specific domains of Rep responsible for VIM5 induction remain poorly characterized. Although Rep proteins from several geminiviruses act as viral suppressors of RNA silencing (VSRs), whether BSCTV Rep also possesses VSR activity remains to be illustrated. In this study, we employed a transient expression system in the 16c-GFP transgenic and the wild-type Nicotiana benthamiana plants to analyze the VSR and the VIM5-inducing activities of different truncated Rep proteins haboring distinct domains. We found that the N-terminal domain (amino acids 1-180) of Rep suppressed GFP silencing in 16c-GFP transgenic N. benthamiana leaves. The minimal N-terminal fragment (amino acids 1-104) induced VIM5 expression upon co-infiltration, while C-terminal truncations lacked VIM5-inducing activity. Our results indicate that the N-terminal domain of Rep encoded by BSCTV mediates the suppression of RNA silencing and induces VIM5 expression. Thus, our findings contribute to a better understanding of interactions between geminiviral Rep and plant hosts.
Geminiviridae/genetics* ; Nicotiana/metabolism* ; Arabidopsis/metabolism* ; RNA Interference ; Viral Proteins/metabolism* ; Arabidopsis Proteins/metabolism* ; Plants, Genetically Modified/metabolism* ; Protein Domains ; Plant Diseases/virology* ; Methyltransferases/metabolism* ; Ubiquitin-Protein Ligases/metabolism* ; DNA Helicases/genetics*

Humans ; Cardiovascular Diseases ; Enhancer of Zeste Homolog 2 Protein/metabolism* ; Histones ; Methyltransferases

Humans ; Cardiovascular Diseases ; Enhancer of Zeste Homolog 2 Protein/metabolism* ; Histones ; Methyltransferases

OBJECTIVE: To investigate the relationship of the expression levels of protein arginine methyltransferase 5 (PRMT5) and Dickkopf-related protein 3 (DKK3) in the PCa tissue with biochemical recurrence (BR) of the malignancy after radical surgery. METHODS: This study included 105 cases of PCa diagnosed in our hospital from January 2016 to December 2020 and, according to BR within 3 years after surgery, we divided them into a BR (n = 22) and a non-BR group (n = 83). We detected the expressions of PRMT5 and DKK3 in the prostate tissues of the patients by immunohistochemistry, analyzed the correlation of the expression levels of PRMT5 and DKK3 using the Spearman method, and conducted a multivariate analysis of postoperative BR of the malignancy using the Cox multivariate regression model. RESULTS: The positive expression of PRMT5 was significantly higher while that of DKK3 remarkably lower in the PCa than in the adjacent tissue (P<0.05). Spearman correlation analysis showed a negative correlation between the expression levels of PRMT5 and DKK3 in the PCa tissue (r = －0.532, P<0.05). The expressions of PRMT5 and DKK3 were significantly associated with tumor-node-metastasis (TNM) stages, positive surgical margins, peripheral nerve invasion, capsular invasion, seminal vesicle invasion and vascular invasion (P<0.05). The percentage of TNM stages III－IV, the positive expression of PRMT5 and the negative expression of DKK3 were remarkably higher in the BR than in the non-BR group (P<0.05). PRMT5 was found to be an independent risk factor for while DKK3 a protective factor against postoperative BR of PCa in the patients (P<0.05). CONCLUSION PRMT5 is highly while DKK3 lowly expressed in PCa tissue, and their expressions are both closely related to the biochemical recurrence of PCa after radical surgery.
Humans ; Male ; Protein-Arginine N-Methyltransferases/metabolism* ; Prostatectomy ; Prostatic Neoplasms/pathology* ; Neoplasm Recurrence, Local ; Adaptor Proteins, Signal Transducing ; Intercellular Signaling Peptides and Proteins/metabolism* ; Middle Aged ; Immunohistochemistry

The histone methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2)-mediated trimethylation of histone H3 lysine 27 (H3K27me3) regulates neural stem cell proliferation and fate specificity through silencing different gene sets in the central nervous system. Here, we explored the function of EZH2 in early post-mitotic neurons by generating a neuron-specific Ezh2 conditional knockout mouse line. The results showed that a lack of neuronal EZH2 led to delayed neuronal migration, more complex dendritic arborization, and increased dendritic spine density. Transcriptome analysis revealed that neuronal EZH2-regulated genes are related to neuronal morphogenesis. In particular, the gene encoding p21-activated kinase 3 (Pak3) was identified as a target gene suppressed by EZH2 and H3K27me3, and expression of the dominant negative Pak3 reversed Ezh2 knockout-induced higher dendritic spine density. Finally, the lack of neuronal EZH2 resulted in impaired memory behaviors in adult mice. Our results demonstrated that neuronal EZH2 acts to control multiple steps of neuronal morphogenesis during development, and has long-lasting effects on cognitive function in adult mice.
Animals ; Mice ; Enhancer of Zeste Homolog 2 Protein/metabolism* ; Histone Methyltransferases/metabolism* ; Histones/genetics* ; Morphogenesis ; Neuronal Plasticity ; Neurons/metabolism*

Animals ; Carrier Proteins/metabolism* ; Histidine/metabolism* ; Humans ; Methylation ; Methyltransferases/metabolism* ; Neoplasm Proteins/metabolism* ; Neoplasms/metabolism* ; Protein Processing, Post-Translational

Protein lysine methylation is a prevalent post-translational modification (PTM) and plays critical roles in all domains of life. However, its extent and function in photosynthetic organisms are still largely unknown. Cyanobacteria are a large group of prokaryotes that carry out oxygenic photosynthesis and are applied extensively in studies of photosynthetic mechanisms and environmental adaptation. Here we integrated propionylation of monomethylated proteins, enrichment of the modified peptides, and mass spectrometry (MS) analysis to identify monomethylated proteins in Synechocystis sp. PCC 6803 (Synechocystis). Overall, we identified 376 monomethylation sites in 270 proteins, with numerous monomethylated proteins participating in photosynthesis and carbon metabolism. We subsequently demonstrated that CpcM, a previously identified asparagine methyltransferase in Synechocystis, could catalyze lysine monomethylation of the potential aspartate aminotransferase Sll0480 both in vivo and in vitro and regulate the enzyme activity of Sll0480. The loss of CpcM led to decreases in the maximum quantum yield in primary photosystem II (PSII) and the efficiency of energy transfer during the photosynthetic reaction in Synechocystis. We report the first lysine monomethylome in a photosynthetic organism and present a critical database for functional analyses of monomethylation in cyanobacteria. The large number of monomethylated proteins and the identification of CpcM as the lysine methyltransferase in cyanobacteria suggest that reversible methylation may influence the metabolic process and photosynthesis in both cyanobacteria and plants.
Bacterial Proteins/metabolism* ; Lysine/metabolism* ; Methyltransferases/metabolism* ; Photosynthesis ; Protein Processing, Post-Translational ; Synechocystis/growth & development*

N-methyladenosine (mA), catalyzed by the methyltransferase complex consisting of Mettl3 and Mettl14, is the most abundant RNA modification in mRNAs and participates in diverse biological processes. However, the roles and precise mechanisms of mA modification in regulating neuronal development and adult neurogenesis remain unclear. Here, we examined the function of Mettl3, the key component of the complex, in neuronal development and adult neurogenesis of mice. We found that the depletion of Mettl3 significantly reduced mA levels in adult neural stem cells (aNSCs) and inhibited the proliferation of aNSCs. Mettl3 depletion not only inhibited neuronal development and skewed the differentiation of aNSCs more toward glial lineage, but also affected the morphological maturation of newborn neurons in the adult brain. mA immunoprecipitation combined with deep sequencing (MeRIP-seq) revealed that mA was predominantly enriched in transcripts related to neurogenesis and neuronal development. Mechanistically, mA was present on the transcripts of histone methyltransferase Ezh2, and its reduction upon Mettl3 knockdown decreased both Ezh2 protein expression and consequent H3K27me3 levels. The defects of neurogenesis and neuronal development induced by Mettl3 depletion could be rescued by Ezh2 overexpression. Collectively, our results uncover a crosstalk between RNA and histone modifications and indicate that Mettl3-mediated mA modification plays an important role in regulating neurogenesis and neuronal development through modulating Ezh2.
Adenosine ; analogs & derivatives ; metabolism ; Adult Stem Cells ; cytology ; metabolism ; Animals ; Brain ; metabolism ; Cell Differentiation ; genetics ; Cell Proliferation ; Enhancer of Zeste Homolog 2 Protein ; metabolism ; Gene Expression Regulation ; Methyltransferases ; metabolism ; Mice, Inbred C57BL ; Neural Stem Cells ; cytology ; metabolism ; Neurogenesis ; genetics ; Neurons ; cytology ; metabolism ; RNA, Messenger ; genetics ; metabolism

The aim of the present study was to investigate the regulatory effects of histone methylation modifications on the expression of miR-200c, as well as invasion and migration of gastric carcinoma cells. Gastric carcinoma cell line, MGC-803, were treated by 2.5 μmol/L histone methyltransferase inhibitor, DZNep. The expression of miR-200c was detected by real-time quantitative PCR (qRT-PCR). The epithelial-mesenchymal transition (EMT) indicators (ZEB1/2 and E/N-cadherin), EZH2, EED, SUZ12 and H3K27me3 expressions were detected by Western blot. Cell migration and invasion abilities were detected by Transwell and scratch tests. The result showed that, compared with DMSO (control) group, DZNep significantly increased the expression of miR-200c to about 2.1 times, inhibited ZEB1, ZEB2, and N-cadherin expressions, and activated E-cadherin expression; Also, DZNep decreased the protein expressions of EZH2, EED, SUZ12 and H3K27me3; Moreover, DZNep could inhibit MGC-803 cell invasive and migrative abilities, as well as MMP9 expression. These results suggest DZNep raises miR-200c expression to delay the invasion and migration of gastric carcinoma cells, and the underlying mechanisms involve the regulations of EMT-related proteins and polycomb repressive complex 2.
Adenosine ; analogs & derivatives ; pharmacology ; Cadherins ; metabolism ; Cell Line, Tumor ; drug effects ; Cell Movement ; drug effects ; Epithelial-Mesenchymal Transition ; Gene Expression Regulation, Neoplastic ; Homeodomain Proteins ; metabolism ; Humans ; MicroRNAs ; metabolism ; Protein Methyltransferases ; antagonists & inhibitors ; Repressor Proteins ; metabolism ; Transcription Factors ; metabolism ; Zinc Finger E-box Binding Homeobox 2 ; Zinc Finger E-box-Binding Homeobox 1