The roles of eukaryotic DNA methylation in the repression of mRNA transcription and in the formation of heterochromatin have been extensively elucidated over the past several years. However, the role of DNA methylation in transcriptional activation remains a mystery. In particular, it is not known whether the transcriptional activation of methylated DNA is promoter-specific, depends directly on sequence-specific DNA-binding proteins, or is facilitated by the methylation. Here we report that the sequence-specific DNA-binding protein, RFX, previously shown to mediate the transition from an inactive to an active chromatin structure, activates a methylated promoter. RFX is capable of mediating enhanceosome formation on a methylated promoter, thereby mediating a transition from a methylation-dependent repression of the promoter to a methylation-dependent activation of the promoter. These results indicate novel roles for DNA methylation and sequence-specific DNA-binding proteins in transcriptional activation.
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http://dx.doi.org/10.1074/jbc.M504633200 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
Department of Nuclear Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, China.
Epstein-Barr nuclear antigen 1 (EBNA1), a sequence-specific DNA binding protein of Epstein-Barr virus (EBV), is essential for viral genome replication and maintenance and is therefore an attractive target for the therapeutic intervention of EBV-associated cancers. Several EBNA1-specific inhibitors have demonstrated the ability to block EBNA1 function in vitro, but practical delivery strategies for these inhibitors in vivo are still lacking. Here, we report an intelligent hierarchical targeting theranostic nanosystem (denoted as mZGOCS@MnO-P5) that integrates an azide (N3) terminal dual-targeting peptide (N3-P5), a tumor microenvironment-responsive degradable MnO nanosheet, and a mesoporous ZnGaO:Cr, Sn near-infrared persistent luminescence (NIR-PL) nanosphere (mZGOCS).
View Article and Find Full Text PDFJ Biomol Struct Dyn
February 2025
Laboratory of Integrative Genomics, Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, India.
The P53 protein, a cancer-associated transcriptional factor and tumor suppressor, houses a Zn ion in its DNA-binding domain (DBD), essential for sequence-specific DNA binding. However, common mutations at position 273, specifically from Arginine to Histidine and Cysteine, lead to a loss of function as a tumor suppressor, also called DNA contact mutations. The mutant (MT) P53 structure cannot stabilize DNA due to inadequate interaction.
View Article and Find Full Text PDFInt J Biol Sci
December 2024
State Key Laboratory of Systems Medicine for Cancer, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China.
Nuclear receptor subfamily 4 group A member 3 (NR4A3) is a member of the orphan nuclear receptor superfamily, and exhibits transcription factor activity by binding to sequence-specific DNA. Considering that the specific mechanism by which NR4A3 regulates gene transcription in HCC (hepatocellular carcinoma) has not yet been elucidated, our study aimed to explore the transcriptional role of NR4A3 in regulating the target gene CDKN2AIP (CDKN2A interacting protein), which will suppress the development of HCC. Our data show that NR4A3 is downregulated in human HCC tissues, and that low expression of NR4A3 is correlated with poor prognosis, indicating that NR4A3 could act as a tumor suppressor gene in HCC.
View Article and Find Full Text PDFMethods Mol Biol
November 2024
Bioinformatics Group, Babraham Institute, Cambridge, UK.
Elife
November 2024
National Institute for Biotechnology and Information, National Library of Medicine, National Institutes of Health, Bethesda, United States.
Enhancers and promoters are classically considered to be bound by a small set of transcription factors (TFs) in a sequence-specific manner. This assumption has come under increasing skepticism as the datasets of ChIP-seq assays of TFs have expanded. In particular, high-occupancy target (HOT) loci attract hundreds of TFs with often no detectable correlation between ChIP-seq peaks and DNA-binding motif presence.
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