Project description:PRMT6, a type I arginine methyltransferase, di-methylates the arginine residues of both histones and non-histones asymmetrically. Increasing evidence indicates that PRMT6 plays a tumor mediator involved in human malignancies. Here, we aim to uncover the essential role and underlying mechanisms of PRMT6 in promoting glioblastoma (GBM) proliferation. Investigation of PRMT6 expression in glioma tissues demonstrated that PRMT6 is overexpressed, and elevated expression of PRMT6 is negatively correlated with poor prognosis in glioma/GBM patients. Silencing PRMT6 inhibited GBM cell proliferation and induced cell cycle arrest at the G0/G1 phase, while overexpressing PRMT6 had opposite results. Further, we found that PRMT6 attenuates the protein stability of CDKN1B by promoting its degradation. Subsequent mechanistic investigations showed that PRMT6 maintains the transcription of CDC20 by activating histone methylation mark (H3R2me2a), and CDC20 interacts with and destabilizes CDKN1B. Rescue experimental results confirmed that PRMT6 promotes the ubiquitinated degradation of CDKN1B and cell proliferation via CDC20. We also verified that the PRMT6 inhibitor (EPZ020411) could attenuate the proliferative effect of GBM cells. Our findings illustrate that PRMT6, an epigenetic mediator, promotes CDC20 transcription via H3R2me2a to mediate the degradation of CDKN1B to facilitate GBM progression. Targeting PRMT6-CDC20-CDKN1B axis might be a promising therapeutic strategy for GBM.
Project description:PRMT6, a type I arginine methyltransferase, di-methylates the arginine residues of both histones and non-histones asymmetrically. Increasing evidence indicates that PRMT6 plays a tumor mediator involved in human malignancies. Here, we aim to uncover the essential role and underlying mechanisms of PRMT6 in promoting glioblastoma (GBM) proliferation. Investigation of PRMT6 expression in glioma tissues demonstrated that PRMT6 is overexpressed, and elevated expression of PRMT6 is negatively correlated with poor prognosis in glioma/GBM patients. Silencing PRMT6 inhibited GBM cell proliferation and induced cell cycle arrest at the G0/G1 phase, while overexpressing PRMT6 had opposite results. Further, we found that PRMT6 attenuates the protein stability of CDKN1B by promoting its degradation. Subsequent mechanistic investigations showed that PRMT6 maintains the transcription of CDC20 by activating histone methylation mark (H3R2me2a), and CDC20 interacts with and destabilizes CDKN1B. Rescue experimental results confirmed that PRMT6 promotes the ubiquitinated degradation of CDKN1B and cell proliferation via CDC20. We also verified that the PRMT6 inhibitor (EPZ020411) could attenuate the proliferative effect of GBM cells. Our findings illustrate that PRMT6, an epigenetic mediator, promotes CDC20 transcription via H3R2me2a to mediate the degradation of CDKN1B to facilitate GBM progression. Targeting PRMT6-CDC20-CDKN1B axis might be a promising therapeutic strategy for GBM.
Project description:Tight regulation of the APC/C-Cdc20 ubiquitin ligase that targets Cyclin B1 for degradation is important for mitotic fidelity. The spindle assembly checkpoint (SAC) inhibits Cdc20 through the mitotic checkpoint complex (MCC). In addition, phosphorylation of Cdc20 by Cyclin B1-Cdk1 independently inhibits APC/C-Cdc20 activation. This creates a conundrum for how Cdc20 gets activated prior to Cyclin B1 degradation. Here we show that the MCC component BubR1 harbours both Cdc20 inhibition and activation activities, allowing for cross-talk between the two Cdc20 inhibition pathways. Specifically BubR1 acts as a substrate specifier for PP2A-B56 to enable efficient Cdc20 dephosphorylation in the MCC. A mutant Cdc20 mimicking the dephosphorylated state escapes a mitotic checkpoint arrest arguing that restricting Cdc20 dephosphorylation to the MCC is important. Collectively our work reveals how Cdc20 can be dephosphorylated in the presence of Cyclin B1-Cdk1 activity without causing premature anaphase onset.
Project description:To identify transcription factors of PRMT6 which could recruit PRMT6 to target genes, we used affinity purification of avi-tagged PRMT6 in combination with stable isotope labeling of amino acids in cell culture (SILAC) based mass spectrometry. For this, K562 cells were transduced with a lentiviral co expression vector for the BirA-ligase and avi-PRMT6 with a 21 amino acid taq, which is biotinylated in the cells. Cells expressing the BirA-ligase only served as a control. Avi-PRMT6 cells were grown in heavy SILAC medium and control cells in light SILAC medium for seven passages. Nuclear extracts were prepared from 1x108 cells and subjected to avi-PRMT6 affinity purification using magnetic streptavidin beads. Subsequently, the proteins were eluted from the beads. The eluates from the avi-PRMT6 and the control were mixed in a one to one ratio. Subsequently, we performed quantitative mass spectrometry (MS)-based analysis of the PRMT6 interactome.
Project description:Zygotic genome activation (ZGA), which is according to the midblastula transition in zebrafish, is an important event during the maternal-zygotic transition in animals. Our preliminary study and other groupâs works indicate that epigenetic regulations play an essential role in ZGA. Morpholino was employed to knockdown PRMT6. We used microarrays to analyze the global gene expression in prmt6 morphants. prmt6 MO (0.3mM) was injected into the one-two cell zebrafish, prmt6 cMO (0.3mM) injection as a control. At 6 hpf, embryos were classified into three subtypes (normal, mild and severe) and prepared for global gene expression analysis with Affymetrix Zebrafish Genome Arrays. The severe subtype and the control were repeated three times.
Project description:Cdc20 acts as a regulatory protein interacting with many other proteins at multiple points in the cell cycle. Here we tried to explore the novel transcription regulatory function of Cdc20 by means of altering Cdc20 level in HepG2 cells. We transiently over expressed Flag tagged Cdc20 (F) and siRNA mediated knocked down Cdc20(S) in HepG2 cell line and performed whole genome microarray analysis using illumina BeadChip Array. Significantly altered genes were subjected to the analysed by Ingenuity pathway analysis software (Build version: 302937) and crucial cellcycle and apoptotic pathways were found to be altered. These pathways could further be explored as anticancer therapy in liver carcinoma.
Project description:Our data reveal that RNA m6A displays a sharp transition during leukemogenesis and involves in acquiring stem cell properties of leukemia stem cells (LSCs). We find that m6A reader IGF2BP2 and protein arginine methyltransferase PRMT6 play key roles in the acquisition of LSCs properties. Genetical deletion and pharmacological inhibition of PRMT6 delayed AML development. Mechanistically, IGF2BP2 regulates PRMT6 expression by stabilizing its mRNA in an m6A-dependent manner. PRMT6 further suppresses the expression of lipid transporter MFSD2A by establishing inactive H3R2me2a in its promoter region. Loss of PRMT6 and IGF2BP2 upregulates the expression of MFSD2A that increases the uptake of docosahexaenoic acid. Collectively, our findings uncover a critical role of IGF2BP2-PRMT6-MFSD2A signaling axis in AML development, and provide a promising therapeutic strategy for targeting LSCs.
Project description:ES cells are able to self-renew and remain pluripotent. These characteristics are maintained by both genetic and epigenetic regulators. Protein arginine methyltransferase (PRMT) 4 and 5 are shown to be important in early embryonic development and in ES cells. PRMT6-mediated di-methylation of histone H3 at arginine 2 (H3R2me2) can antagonize the tri-methylation of histone H3 at lysine 4, which marks active genes. However, it is unclear whether PRMT6 and PRMT6-mediated H3R2me2 play crucial roles in early embryonic development and ES cell identity. In this study, we investigate their functions using mouse ES cells as the model. We used microarray (Affymetrix GeneChip Mouse Gene 1.0ST) to examine the global change of gene expression in mouse ES cells when Prmt6 was overexpressed and identified distinct classes of genes that are up-regulated and down-regulated during this process. Mouse ES cells were transfected with either pCAGIP.puro empty vector (control) or Prmt6 overexpressing plasmid (P+6 OE). After 3 days of selection by puromycin, cells from both populations were subjected to RNA extraction and hybridization on Affymetrix microarrays.
Project description:Protein arginine methyltransferase 6 (PRMT6) is an epigenetic regulator of fundamental cellular processes, such as gene expression and DNA repair. Asymmetric dimethylation of histone H3 at arginine 2 (H3R2me2a) is the major histone modification catalyzed by PRMT6. To identify the genome-wide deposition and transcriptional impact of H3R2me2a, we established PRMT6 deletion in a human cell model of neural differentiation. These knockout cells show severe neural differentiation defects. ChIP-seq profiling reveals that H3R2me2a is present at promoter as well as non-promoter sites in a PRMT6-dependent manner. Loss of H3R2me2a causes enhanced H3K4me3 deposition and target gene transcription supporting a genome-wide repressive nature of H3R2me2a. Intriguingly, the non-promoter H3R2me2a peaks co-localize with active enhancer marks, such as H3K4me1 and H3K27ac.