Protein arginine methyltransferase 5 (Prmt5) promotes gene expression of peroxisome proliferator-activated receptor γ2 (PPARγ2) and its target genes during adipogenesis.
ABSTRACT Regulation of adipose tissue formation by adipogenic-regulatory proteins has long been a topic of interest given the ever-increasing health concerns of obesity and type 2 diabetes in the general population. Differentiation of precursor cells into adipocytes involves a complex network of cofactors that facilitate the functions of transcriptional regulators from the CCATT/enhancer binding protein, and the peroxisome proliferator-activated receptor (PPAR) families. Many of these cofactors are enzymes that modulate the structure of chromatin by altering histone-DNA contacts in an ATP-dependent manner or by posttranslationally modifying the histone proteins. Here we report that inhibition of protein arginine methyltransferase 5 (Prmt5) expression in multiple cell culture models for adipogenesis prevented the activation of adipogenic genes. In contrast, overexpression of Prmt5 enhanced adipogenic gene expression and differentiation. Chromatin immunoprecipitation experiments indicated that Prmt5 binds to and dimethylates histones at adipogenic promoters. Furthermore, the presence of Prmt5 promoted the binding of ATP-dependent chromatin-remodeling enzymes and was required for the binding of PPARγ2 at PPARγ2-regulated promoters. The data indicate that Prmt5 acts as a coactivator for the activation of adipogenic gene expression and promotes adipogenic differentiation.
- Cell 11/1974; 3(2):127-33. · 31.96 Impact Factor
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ABSTRACT: The role of hSWI/SNF complexes in transcriptional activation is well characterized; however, little is known about their function in transcriptional repression. We have previously shown that subunits of the mSin3A/histone deacetylase 2 (HDAC2) corepressor complex copurify with hSWI/SNF complexes. Here we show that the type II arginine-specific methyltransferase PRMT5, which is involved in cyclin E repression, can be found in association with Brg1 and hBrm-based hSWI/SNF complexes. We also show that hSWI/SNF-associated PRMT5 can methylate hypoacetylated histones H3 and H4 more efficiently than hyperacetylated histones H3 and H4. Protein-protein interaction studies indicate that PRMT5 and mSin3A interact with the same hSWI/SNF subunits as those targeted by c-Myc. These observations prompted us to examine the expression profile of the c-Myc target genes, carbamoyl-phosphate synthase-aspartate carbamoyltransferase-dihydroorotase (cad) and nucleolin (nuc). We found that cad repression is altered in cells that express inactive Brg1 and in cells treated with the HDAC inhibitor depsipeptide. Using chromatin immunoprecipitation assays, we found that Brg1, mSin3A, HDAC2, and PRMT5 are directly recruited to the cad promoter. These results suggest that hSWI/SNF complexes, through their ability to interact with activator and repressor proteins, control expression of genes involved in cell growth and proliferation.Molecular and Cellular Biology 12/2003; 23(21):7475-87. · 5.37 Impact Factor
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ABSTRACT: Differentiation of 3T3-L1 preadipocytes into adipocytes is accompanied by increased expression of the nuclear protein C/EBP (CCAAT/enhancer binding protein) and by transcriptional activation of a group of adipose-specific genes. We report here the isolation of the murine C/EBP gene and the characterization of its promoter. Consistent with its proposed role in coordinating transcription during preadipocyte differentiation, an increase in the rate of transcription of the C/EBP gene precedes that of several adipose-specific genes whose promoters are transactivated by C/EBP. DNase I cleavage-inhibition patterns (footprinting) of the C/EBP gene promoter by nuclear factors from differentiated and undifferentiated 3T3-L1 cells identified two sites of differential factor binding. One site in the C/EBP gene promoter between nucleotides -252 and -239 binds a nuclear factor(s) present in preadipocytes that is lost or modified upon differentiation. Another site, between nucleotides -203 and -176, exhibits different but overlapping footprints by nuclear factors present in differentiated and undifferentiated cells. Gel retardation analysis with oligonucleotides corresponding to these sites revealed protein-oligonucleotide complexes containing these differentially expressed nuclear factors. The factor present in differentiated cells that binds at this site was identified as C/EBP (possibly in heterodimeric form with a homologous leucine-zipper protein), suggesting that C/EBP may regulate expression of its own gene.Proceedings of the National Academy of Sciences 04/1991; 88(6):2593-7. · 9.74 Impact Factor