We have investigated the function and mechanisms of the CARM1-SNF5 complex in T3-dependent transcriptional activation. Using specific small interfering RNAs (siRNA) to knock down coactivators in HeLa alpha2 cells, we found that coactivator associated arginine methyltransferase 1 (CARM1) and SWI/SNF complex component 5 (SNF5) are important for T3-dependent transcriptional activation. The CARM1- SWI/SNF chromatin remodeling complex serves as a mechanism for the rapid reversal of H3-K9 methylation. Importantly, siRNA treatment against CARM1 and/or SNF5 increased the recruitment of HMTase G9a to the type 1 deiodinase (D1) promoter even with T3. Knocking- down either CARM1 or SNF5 also inhibited the down- regulation of histone macroH2A, which is correlated with transcriptional activation. Finally, knocking down CARM1 and SNF5 by siRNA impaired the association of these coactivators to the D1 promoter, suggesting functional importance of CARM1- SNF5 complex in T3-dependent transcriptional activation.
Chromosomal Proteins, Non-Histone/*physiology ; DNA-Binding Proteins/*physiology ; Hela Cells ; Histone-Lysine N-Methyltransferase/*metabolism ; Histones/metabolism ; Humans ; Iodide Peroxidase/metabolism ; Methylation ; Promoter Regions, Genetic ; Protein Methyltransferases ; Protein-Arginine N-Methyltransferase/*physiology ; Receptors, Thyroid Hormone/*physiology ; Transcription Factors/*physiology ; *Transcriptional Activation

Encystation is an essential process for Acanthamoeba survival under nutrient-limiting conditions and exposure to drugs. The expression of several genes has been observed to increase or decrease during encystation. Epigenetic processes involved in regulation of gene expression have been shown to play a role in several pathogenic parasites. In the present study, we identified the protein arginine methyltransferase 5 (PRMT5), a known epigenetic regulator, in Acanthamoeba castellanii. PRMT5 of A. castellanii (AcPRMT5) contained domains found in S-adenosylmethionine-dependent methyltransferases and in PRMT5 arginine-N-methyltransferase. Expression levels of AcPRMT5 were increased during encystation of A. castellanii. The EGFP-PRMT5 fusion protein was mainly localized in the nucleus of trophozoites. A. castellanii transfected with siRNA designed against AcPRMT5 failed to form mature cysts. The findings of this study lead to a better understanding of epigenetic mechanisms behind the regulation of encystation in cyst-forming pathogenic protozoa.
Acanthamoeba castellanii ; Acanthamoeba* ; Epigenesis, Genetic ; Epigenomics ; Gene Expression Regulation ; Methyltransferases ; Parasites ; Protein-Arginine N-Methyltransferases* ; RNA, Small Interfering ; Trophozoites

Glucose homeostasis is tightly controlled by the regulation of glucose production in the liver and glucose uptake into peripheral tissues, such as skeletal muscle and adipose tissue. Under prolonged fasting, hepatic gluconeogenesis is mainly responsible for glucose production in the liver, which is essential for tissues, organs, and cells, such as skeletal muscle, the brain, and red blood cells. Hepatic gluconeogenesis is controlled in part by the concerted actions of transcriptional regulators. Fasting signals are relayed by various intracellular enzymes, such as kinases, phosphatases, acetyltransferases, and deacetylases, which affect the transcriptional activity of transcription factors and transcriptional coactivators for gluconeogenic genes. Protein arginine methyltransferases (PRMTs) were recently added to the list of enzymes that are critical for regulating transcription in hepatic gluconeogenesis. In this review, we briefly discuss general aspects of PRMTs in the control of transcription. More specifically, we summarize the roles of four PRMTs: PRMT1, PRMT 4, PRMT 5, and PRMT 6, in the control of hepatic gluconeogenesis through specific regulation of FoxO1- and CREB-dependent transcriptional events.
Acetyltransferases ; Adipose Tissue ; Arginine* ; Brain ; Erythrocytes ; Fasting ; Gluconeogenesis ; Glucose* ; Homeostasis ; Liver ; Metabolism* ; Methyltransferases* ; Muscle, Skeletal ; Phosphoric Monoester Hydrolases ; Phosphotransferases ; Protein-Arginine N-Methyltransferases ; Transcription Factors

Protein arginine methyltransferase (PRMT) is an important epigenetic regulator in eukaryotic cells. During encystation, an essential process for Acanthamoeba survival, the expression of a lot of genes involved in the encystation process has to be regulated in order to be induced or inhibited. However, the regulation mechanism of these genes is yet unknown. In this study, the full-length 1,059 bp cDNA sequence of Acanthamoeba castellanii PRMT1 (AcPRMT1) was cloned for the first time. The AcPRMT1 protein comprised of 352 amino acids with a SAM-dependent methyltransferase PRMT-type domain. The expression level of AcPRMT1 was highly increased during encystation of A. castellanii. The EGFP-AcPRMT1 fusion protein was distributed over the cytoplasm, but it was mainly localized in the nucleus of Acanthamoeba. Knock down of AcPRMT1 by synthetic siRNA with a complementary sequence failed to form mature cysts. These findings suggested that AcPRMT1 plays a critical role in the regulation of encystation of A. castellanii. The target gene of AcPRMT1 regulation and the detailed mechanisms need to be investigated by further studies.
Acanthamoeba castellanii* ; Acanthamoeba* ; Amino Acids ; Clone Cells ; Cytoplasm ; DNA, Complementary ; Epigenomics ; Eukaryotic Cells ; Protein-Arginine N-Methyltransferases* ; RNA, Small Interfering

An accelerating effect of methyl-deficient diet (MDD) on hepatocarcinogenesis and methylation pattern of nuclear protein(s) by S-adenosylmethionine: protein arginine N-methyltransferase (protein methylase I, PM-I) have been studied with 3'-methyl-4-dimethyl- aminoazobenzene(MeDAB)-treated rats. The MDD+MeDAB-fed group produced typical cancer cells in the liver almost two weeks earlier than the control synthetic diet (CSD)+MeDAB-fed group. Protein methylase I (PM-I) activity in the livers of MDD alone fed rats began to increase at around 2 weeks after MDD-feeding, reaching a peak at 4 weeks and declining thereafter. When nuclei isolated either from normal livers or from cholangiocarcinoma cells were incubated with PM-I preparation from normal liver, 16 and 23-kDa nuclear proteins were the major methylated proteins, regardless of the source of the nuclei. However, when the above mentioned nuclei were incubated with PM-I preparations either from MDD alone fed livers or MDD+ MeDAB-induced cholangiocarcinoma cells, the methylation of 23-kDa protein was not detected. The result suggests that there is a hitherto-unknown PM-I specific to 23 kDa nuclear protein which was lost during methyl deficient diet feeding and hepatocarcinogenesis. The N-terminal 20 amino acids sequence of the 23-kDa protein was found to be (1)Gly-Val-Pro-Leu-(5)X-Arg-Leu-Phe-Asp-(10)His-Ala-Met-Leu-Gln-(15)Ala -His-Arg-Ala-His-(20)Glu, having 94.7% sequence homology with human chorionic somatomammotropin precursor A and B.
Amino Acids ; Animals ; Arginine ; Carcinogens ; Carcinoma, Hepatocellular ; Cell Differentiation ; Cell Division ; Cell Proliferation* ; Cholangiocarcinoma ; Diet ; Food, Formulated ; Liver ; Methylation* ; Nuclear Proteins ; p-Dimethylaminoazobenzene ; Placental Lactogen ; Protein Methyltransferases ; Protein-Arginine N-Methyltransferases ; Rats ; S-Adenosylmethionine ; Sequence Homology

OBJECTIVETo screen the asymmetric dimethyl arginines (ADMA)-containing proteins which could combine with protein arginine methyltransferase 1 (PRMT1).

METHODSWestern blot was adopted to identify the expression of PRMT1 and the proteins with ADMA in glioma cell lines and normal brain tissues, and then to detect the changes of ADMA level after knock-down of PRMT1 with RNAi transfection in U87MG cells. Co-Immunoprecipitation (Co-IP), western blot, and sliver staining were employed to screen the candidate binding proteins of PRMT1. Then liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify the binding proteins of PRMT1.

RESULTSThe expression of PRMT1 and some levels of ADMA were higher in glioma cell lines than in normal brain tissues. After knocking down PRMT1, some ADMA levels were found declined. After screening the binding proteins of PRMT1 with Co-IP and LC-MS/MS, 26 candidate binding proteins were identified. Among them, 6 candidate proteins had higher ions scores (> 38) and bioinformation analysis predicted that SEC23-IP, ANKHD1-EIF4EBP3 protein, and 1-phosphatidylinositol-3-phosphate 5-kinase isoform 2 had possible methylated aginine sites.

CONCLUSIONSThe high expression of PRMT1 in glioma may induce the change of ADMA levels. Altogether 26 candidate proteins were identified, which contain ADMA and specifically bind with PRMT1.

Arginine ; analogs & derivatives ; analysis ; Cell Line, Tumor ; Chromatography, Liquid ; Glioma ; chemistry ; Humans ; Immunoprecipitation ; Protein-Arginine N-Methyltransferases ; analysis ; physiology ; Repressor Proteins ; analysis ; physiology ; Substrate Specificity ; Tandem Mass Spectrometry

OBJECTIVETo observe the expression of protein arginine N-methyltransferase (PRMT) genes in the lung and spleen of E3 rats with acute asthma.

METHODSE3 rats with ovalbumin-induced pulmonary inflammation were divided into two groups (n=10), and the validity of the acute asthma model was evaluated by histological observation with HE and PAS staining and by measurement of NO production. Semi-quantitative RT-PCR was employed to detect the expressions of PRMT1-PRMT6 genes in the lung and spleen tissues of the rats.

RESULTSIn the lung tissue of the asthmatic rats, the gene expressions of PRMT1 (P<0.01), PRMT2 (P<0.01), PRMT3 (P<0.05) and PRMT5 (P<0.05) were significantly increased, but the expression of PRMT4 gene (P<0.05) was significantly decreased as compared with those in the control tissue. In the spleen tissue of the asthmatic rats, the expressions of PRMT2 (P<0.05) and PRMT5 genes (P<0.05) showed a significant increase as compared with those in the control rat tissue.

CONCLUSIONThe gene expressions of PRMTs vary significantly between asthmatic rats and control rats, suggesting that PRMTs play an important role in the post-translational modification process of asthma-related genes.

Acute Disease ; Animals ; Asthma ; enzymology ; Female ; Male ; Protein Processing, Post-Translational ; Protein-Arginine N-Methyltransferases ; classification ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Inbred Strains

BACKGROUND: Protein arginine methyltransferase 1 (PRMT1) is a major enzyme responsible for the formation of methylarginine in mammalian cells. Recent studies have revealed that PRMT1 plays important roles in the development of various tissues. However, its role in pancreas development has not yet been elucidated. METHODS: Pancreatic progenitor cell-specific Prmt1 knock-out (Prmt1 PKO) mice were generated and characterized for their metabolic and histological phenotypes and their levels of Neurog3 gene expression and neurogenin 3 (NGN3) protein expression. Protein degradation assays were performed in mPAC cells. RESULTS: Prmt1 PKO mice showed growth retardation and a severely diabetic phenotype. The pancreatic size and β-cell mass were significantly reduced in Prmt1 PKO mice. Proliferation of progenitor cells during the secondary transition was decreased and endocrine cell differentiation was impaired. These defects in pancreas development could be attributed to the sustained expression of NGN3 in progenitor cells. Protein degradation assays in mPAC cells revealed that PRMT1 was required for the rapid degradation of NGN3. CONCLUSION: PRMT1 critically contributes to pancreas development by destabilizing the NGN3 protein.
Animals ; Diabetes Mellitus ; Endocrine Cells ; Gene Expression ; Islets of Langerhans ; Mice ; Pancreas ; Phenotype ; Protein Stability ; Protein-Arginine N-Methyltransferases ; Proteolysis ; Stem Cells

BACKGROUNDGlioblastoma multiforme (GBM) is the most common and lethal primary brain tumor in adults. Magnetic resonance imaging (MRI) is routinely used in the diagnosis, characterization and clinical management of GBM. The diagnosis and treatment of GBM is largely guided by histopathology and immunohistochemistry. This study aimed to identify the relationship between magnetic resonance features and molecular pathology of GBM.

METHODSMRI images of 43 glioblastoma patients were collected. Four imaging features, degree of edema, contrast tumor enhanced/T2 ratio, multiple lesions and tumor across the midline, were selected to identify their relationship with P53, Ki-67 and O(6)-methylguanine-DNA methyltransferase (MGMT) expression in patients with GBM. The relationship between imaging features and molecular pathology was studied by chi-square test using the software SPSS 13.0.

RESULTSHigh expression of P53 was found correlated with low contrast tumor enhanced/T2 ratio, low expression of Ki-67 was correlated with multiple lesions and high expression of KI-67 may be related with tumor across the midline, low expression of MGMT was correlated with edema.

CONCLUSIONSome MRI features such as the degree of edema, contrast tumor enhanced/T2 ratio, multiple lesions and tumor acrossing the midline are correlated with P53, Ki-67 and MGMT of GBM.

Edema ; metabolism ; pathology ; Glioblastoma ; metabolism ; pathology ; Humans ; In Vitro Techniques ; Ki-67 Antigen ; metabolism ; Magnetic Resonance Imaging ; methods ; O(6)-Methylguanine-DNA Methyltransferase ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

Protein arginine methylation is important for a variety of cellular processes including transcriptional regulation, mRNA splicing, DNA repair, nuclear/cytoplasmic shuttling and various signal transduction pathways. However, the role of arginine methylation in protein biosynthesis and the extracellular signals that control arginine methylation are not fully understood. Basic fibroblast growth factor (bFGF) has been identified as a potent stimulator of myofibroblast dedifferentiation into fibroblasts. We demonstrated that symmetric arginine dimethylation of eukaryotic elongation factor 2 (eEF2) is induced by bFGF without the change in the expression level of eEF2 in mouse embryo fibroblast NIH3T3 cells. The eEF2 methylation is preceded by ras-raf-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK1/2)-p21(Cip/WAF1) activation, and suppressed by the mitogen-activated protein kinase (MAPK) inhibitor PD98059 and p21(Cip/WAF1) short interfering RNA (siRNA). We determined that protein arginine methyltransferase 7 (PRMT7) is responsible for the methylation, and that PRMT5 acts as a coordinator. Collectively, we demonstrated that eEF2, a key factor involved in protein translational elongation is symmetrically arginine-methylated in a reversible manner, being regulated by bFGF through MAPK signaling pathway.
Animals ; Arginine ; Cell Dedifferentiation ; Cyclin-Dependent Kinase Inhibitor p21/genetics/metabolism ; Elongation Factor 2 Kinase/*metabolism ; Fibroblast Growth Factor 2/*metabolism ; Fibroblasts/*metabolism/pathology ; Flavonoids/pharmacology ; MAP Kinase Signaling System/drug effects/genetics ; Methylation ; Mice ; Mitogen-Activated Protein Kinases/antagonists & inhibitors ; Myofibroblasts/pathology ; NIH 3T3 Cells ; Protein Methyltransferases/*metabolism ; Protein-Arginine N-Methyltransferases/*metabolism ; RNA, Small Interfering/genetics