Project description:Protein arginine methyltransferase 1 (Prmt1) is known as the major Type-I protein arginine methyltransferase that deposits asymmetrical dimethylarginine (ADMA) in both histone and non-histone substrates. Nonetheless, how Prmt1 and its downstream signalling through substrate methylation function in the male germline development remains poorly understood. In this study, we discovered that Prmt1 is predominantly present in the spermatogonial population during mouse spermatogenesis. Using three Cre-mediated conditional Prmt1 knockout mouse lines, we observed that Prmt1 is essential for the maintenance of spermatogonial cells and Prmt1-deposited ADMA marks coordinate an inherent homeostasis among three types of substrate methylation. In conjunction with high-throughput Cut&Tag and modified mini-bulk Smart-seq2 analyses, we unveiled that Prmt1-mediated H4R3me2a mark enriched in the promoter region, together with other histone arginine methylations, drives a global transcriptomic landscape that maintains the regular gene expression and alternative splicing. Collectively, we provide the genetic evidence showing the essential role of Prmt1-deposited arginine methylation in the establishment of transcriptional homeostasis, and shed light on the methylarginine signalling pathway in orchestrating spermatogonial development in the mammalian germline.
Project description:PRMT1 is the major Arginine methyltransferase in mammalian cells and its over-expression in human cancer has been linked to poor response to cancer therapy. Here, combining mass spectrometry-based global methyl-proteomics with genome-wide mRNA expression profiling, we identify PRMT1 and its associated Arginine methylation as a regulatory hubs controlling cancer cell response to replicative stress agents. We show that DNA-PK binds to PRMT1 and regulates both its subcellular localization and activity, leading to PRMT1 recruitment to drug-stalled replication forks and channelling its methyl-transferase activity from its soluble targets towards Arginine 3 of histone H4. This DNA-PK-PRMT1 axis is required for the induction of the Senescence-Associated Secretory Phenotype, which sustains cell cycle arrest and protects cells from apoptosis. Our data show that Arginine-methylation regulates the adaptive response of cancer cell to replicative stress agents and might be targeted to sensitize cancer cells to genotoxic chemotherapeutics
Project description:PRMT1 is thought to be responsible for the majority of PRMT activity in Toxoplasma gondii, but its exact function is unknown. We generated T. gondii mutants lacking PRMT1 (∆prmt1) by deletion of the PRMT1 gene. ∆prmt1 parasites exhibit morphological defects during cell division and grow slowly, and this phenotype reverses in the complemented strain ∆prmt::PRMT1mRFP. PRMT1 localizes primarily in the cytoplasm with enrichment at the centrosome, and the strain lacking PRMT1 is unable to segregate progeny accurately. Unlike wild-type and complemented parasites, ∆prmt1 parasites have abnormal daughter buds, perturbed centrosome stoichiometry, and loss of synchronous replication. Whole genome expression profiling demonstrated differences in expression of cell cycle regulated genes in ∆prmt1 relative to the complemented ∆prmt1::PRMT1mRFP and parental wild-type strains, but these changes did not correlate with a specific block in cell cycle. Although PRMT1’s primary biological function was previously proposed to be methylation of histones, our genetic studies suggest that the most critical function of PRMT1 is within the centrosome as a regulator of daughter cell counting to assure the proper replication of the parasite. RNA samples were isolated in triplicates from RH-hxgprt parent strain (W), PRMT1 knockout (K) strain and PRMT1 knockout strain complemented with RFP-tagged PRMT1 protein (C). Parasites were grown for 32h at 37C. Samples were hybridized to the Toxoplasma gondii Affymetrix microarray (ToxoGeneChip: http://ancillary.toxodb.org/docs/Array-Tutorial.html). Hybridization data was preprocessed with Robust Multi-array Average (RMA) and normalized using per chip and per gene median polishing and analyzed using the software package GeneSpring GX (Agilent Technologies).
Project description:Heterogeneous gene expression is a characteristic feature of stem cells and is essential for steering lineage choices. However, the molecular mechanisms of heterogeneity remain largely unknown. Here, we report that depletion of protein arginine methyltransferase 1 (Prmt1) in mouse embryonic stem (ES) cells heterogeneously induces the expression of primitive endoderm (PrE) genes, consequently biasing the cells to fluctuate toward the extraembryonic endoderm stem (XEN) cell fate. Furthermore, the pluripotency factor Klf4 is arginine-methylated by Prmt1 at arginine 396 (R396), which is required for recruitment of the mSin3a/HDAC complex to silence PrE genes. Importantly, when methylation is disrupted by a Prmt1 knockout, a Prmt1 inhibitor, or a blocked methylation site in Klf4, ES cells are predisposed to XEN induction. Our data demonstrate the importance of Prmt1 in the fluctuating heterogeneity of ES cells and reveal a regulatory mechanism for cell fate decisions that is centered on Klf4 methylation mediated by Prmt1.
Project description:PRMT1 is thought to be responsible for the majority of PRMT activity in Toxoplasma gondii, but its exact function is unknown. We generated T. gondii mutants lacking PRMT1 (∆prmt1) by deletion of the PRMT1 gene. ∆prmt1 parasites exhibit morphological defects during cell division and grow slowly, and this phenotype reverses in the complemented strain ∆prmt::PRMT1mRFP. PRMT1 localizes primarily in the cytoplasm with enrichment at the centrosome, and the strain lacking PRMT1 is unable to segregate progeny accurately. Unlike wild-type and complemented parasites, ∆prmt1 parasites have abnormal daughter buds, perturbed centrosome stoichiometry, and loss of synchronous replication. Whole genome expression profiling demonstrated differences in expression of cell cycle regulated genes in ∆prmt1 relative to the complemented ∆prmt1::PRMT1mRFP and parental wild-type strains, but these changes did not correlate with a specific block in cell cycle. Although PRMT1’s primary biological function was previously proposed to be methylation of histones, our genetic studies suggest that the most critical function of PRMT1 is within the centrosome as a regulator of daughter cell counting to assure the proper replication of the parasite.
Project description:Fusion protein AML1-ETO resulted from t(8;21) translocation is highly related to leukemia development. We have previously shown that the expression of AE9a, a spliced form of AML1-ETO, can rapidly cause leukemia in mouse. To understand how AML1-ETO is involved in leukemia development, we used AE9a leukemia model to identify a novel AE9a interacting proteins PRMT1 (protein arginine methyltransferase 1) from primary leukemic cells expressing AE9a. To examine whether PRMT1 is involved in AE9a-mediated transcription regulation, genome wide gene expression analysis is carried out in hematopoietic cell line K562 (wild type or AE9a expressing) treated with (-) control siRNA or siPRMT1. Wild type or AE9a-expressing K562 cells with control siRNA or siPRMT1 in triplicate