The arginine methyltransferase PRMT6 regulates cell proliferation and senescence through transcriptional repression of tumor suppressor genes.
The protein arginine methyltransferase 6 (PRMT6) is a coregulator of gene expression and executes its repressing as well as activating function by asymmetric dimethylation of histone H3 at R2 (H3 R2me2a). Given that elevated expression levels of PRMT6 have been reported in various cancer types, we explore here its role in cell proliferation and senescence. We find that knockdown of PRMT6 results in proliferation defects of transformed as well as non-transformed cells, causes G1-phase arrest and induces senescence. This phenotype is accompanied by transcriptional upregulation of important cell cycle regulators, most prominently the cyclin-dependent kinase (CDK) inhibitor gene p21 (p21(CIP1/WAF1), CDKN1A) and p16 (p16(INK4A), CDKN2A). Chromatin immuno-precipitation analysis reveals that the p21 gene is a direct target of PRMT6 and the corresponding histone mark H3 R2me2a. Using a cell model of oncogene-induced senescence (OIS), in which p21 is an essential activator of the senescent phenotype, we show that PRMT6 expression declines upon induction of senescence and conversely p21 gene expression increases. Moreover, overexpression of PRMT6 leads to reduced levels of OIS. These findings indicate that the transcriptional repressor activity of PRMT6 facilitates cell proliferation and blocks senescence by regulation of tumor suppressor genes and that this might contribute to the oncogenic capacity of PRMT6.
Institute for Molecular Biology and Tumor Research, University of Marburg, Emil-Mannkopff-Strasse 2, 35032 Marburg, Germany.
Claudia
C
Stein
Stefanie
S
Riedl
Diana
D
Rüthnick
René Reiner
RR
Nötzold
Uta-Maria
UM
Bauer
D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016922:Cellular Senescence / Q000235:genetics*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics; D005786:Gene Expression Regulation; D016147:Genes, Tumor Suppressor; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D011484:Protein-Arginine N-Methyltransferases / Q000235:genetics / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D009687:Nuclear Proteins; D012097:Repressor Proteins; C447833:PRMT6 protein, human; D011484:Protein-Arginine N-Methyltransferases