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DNA methylation of a GC repressor element in the smooth muscle myosin heavy chain promoter facilitates binding of the Notch-associated transcription factor, RBPJ/CSL1.
Arterioscler Thromb Vasc Biol. 2014 Dec; 34(12):2624-31.AT

Abstract

OBJECTIVE

The goal of the present study was to identify novel mechanisms that regulate smooth muscle cell (SMC) differentiation marker gene expression.

APPROACH AND RESULTS

We demonstrate that the CArG-containing regions of many SMC-specific promoters are imbedded within CpG islands. A previously identified GC repressor element in the SM myosin heavy chain (MHC) promoter was highly methylated in cultured aortic SMC but not in the aorta, and this difference was inversely correlated with SM MHC expression. Using an affinity chromatography/mass spectroscopy-based approach, we identified the multifunctional Notch transcription factor, recombination signal binding protein for immunoglobulin κ J region (RBPJ), as a methylated GC repressor-binding protein. RBPJ protein levels and binding to the endogenous SM MHC GC repressor were enhanced by platelet-derived growth factor-BB treatment. A methylation mimetic mutation to the GC repressor that facilitated RBPJ binding inhibited SM MHC promoter activity as did overexpression of RBPJ. Consistent with this, knockdown of RBPJ in phenotypically modulated human aortic SMC enhanced endogenous SMC marker gene expression, an effect likely mediated by increased recruitment of serum response factor and Pol II to the SMC-specific promoters. In contrast, the depletion of RBPJ in differentiated transforming growth factor-β-treated SMC inhibited SMC-specific gene activation, supporting the idea that the effects of RBPJ/Notch signaling are context dependent.

CONCLUSIONS

Our results indicate that methylation-dependent binding of RBPJ to a GC repressor element can negatively regulate SM MHC promoter activity and that RBPJ can inhibit SMC marker gene expression in phenotypically modulated SMC. These results will have important implications on the regulation of SMC phenotype and on Notch-dependent transcription.

Authors+Show Affiliations

From the Department of Pathology, University of North Carolina, Chapel Hill.From the Department of Pathology, University of North Carolina, Chapel Hill.From the Department of Pathology, University of North Carolina, Chapel Hill.From the Department of Pathology, University of North Carolina, Chapel Hill.From the Department of Pathology, University of North Carolina, Chapel Hill. cmack@med.unc.edu.

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

25324571

Citation

Rozenberg, Julian M., et al. "DNA Methylation of a GC Repressor Element in the Smooth Muscle Myosin Heavy Chain Promoter Facilitates Binding of the Notch-associated Transcription Factor, RBPJ/CSL1." Arteriosclerosis, Thrombosis, and Vascular Biology, vol. 34, no. 12, 2014, pp. 2624-31.
Rozenberg JM, Tesfu DB, Musunuri S, et al. DNA methylation of a GC repressor element in the smooth muscle myosin heavy chain promoter facilitates binding of the Notch-associated transcription factor, RBPJ/CSL1. Arterioscler Thromb Vasc Biol. 2014;34(12):2624-31.
Rozenberg, J. M., Tesfu, D. B., Musunuri, S., Taylor, J. M., & Mack, C. P. (2014). DNA methylation of a GC repressor element in the smooth muscle myosin heavy chain promoter facilitates binding of the Notch-associated transcription factor, RBPJ/CSL1. Arteriosclerosis, Thrombosis, and Vascular Biology, 34(12), 2624-31. https://doi.org/10.1161/ATVBAHA.114.304634
Rozenberg JM, et al. DNA Methylation of a GC Repressor Element in the Smooth Muscle Myosin Heavy Chain Promoter Facilitates Binding of the Notch-associated Transcription Factor, RBPJ/CSL1. Arterioscler Thromb Vasc Biol. 2014;34(12):2624-31. PubMed PMID: 25324571.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - DNA methylation of a GC repressor element in the smooth muscle myosin heavy chain promoter facilitates binding of the Notch-associated transcription factor, RBPJ/CSL1. AU - Rozenberg,Julian M, AU - Tesfu,Daniel B, AU - Musunuri,Srilaxmi, AU - Taylor,Joan M, AU - Mack,Christopher P, Y1 - 2014/10/16/ PY - 2014/10/18/entrez PY - 2014/10/18/pubmed PY - 2015/4/25/medline KW - RBPJ protein, human KW - epigenetics KW - muscle, smooth KW - serum response factor SP - 2624 EP - 31 JF - Arteriosclerosis, thrombosis, and vascular biology JO - Arterioscler. Thromb. Vasc. Biol. VL - 34 IS - 12 N2 - OBJECTIVE: The goal of the present study was to identify novel mechanisms that regulate smooth muscle cell (SMC) differentiation marker gene expression. APPROACH AND RESULTS: We demonstrate that the CArG-containing regions of many SMC-specific promoters are imbedded within CpG islands. A previously identified GC repressor element in the SM myosin heavy chain (MHC) promoter was highly methylated in cultured aortic SMC but not in the aorta, and this difference was inversely correlated with SM MHC expression. Using an affinity chromatography/mass spectroscopy-based approach, we identified the multifunctional Notch transcription factor, recombination signal binding protein for immunoglobulin κ J region (RBPJ), as a methylated GC repressor-binding protein. RBPJ protein levels and binding to the endogenous SM MHC GC repressor were enhanced by platelet-derived growth factor-BB treatment. A methylation mimetic mutation to the GC repressor that facilitated RBPJ binding inhibited SM MHC promoter activity as did overexpression of RBPJ. Consistent with this, knockdown of RBPJ in phenotypically modulated human aortic SMC enhanced endogenous SMC marker gene expression, an effect likely mediated by increased recruitment of serum response factor and Pol II to the SMC-specific promoters. In contrast, the depletion of RBPJ in differentiated transforming growth factor-β-treated SMC inhibited SMC-specific gene activation, supporting the idea that the effects of RBPJ/Notch signaling are context dependent. CONCLUSIONS: Our results indicate that methylation-dependent binding of RBPJ to a GC repressor element can negatively regulate SM MHC promoter activity and that RBPJ can inhibit SMC marker gene expression in phenotypically modulated SMC. These results will have important implications on the regulation of SMC phenotype and on Notch-dependent transcription. SN - 1524-4636 UR - https://www.unboundmedicine.com/medline/citation/25324571/DNA_methylation_of_a_GC_repressor_element_in_the_smooth_muscle_myosin_heavy_chain_promoter_facilitates_binding_of_the_Notch_associated_transcription_factor_RBPJ/CSL1_ L2 - http://www.ahajournals.org/doi/full/10.1161/ATVBAHA.114.304634?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -