Transcriptional regulation by RNA polymerase II is associated with changes in chromatin structure. Activated and promoter-bound heat shock transcription factor 1 (HSF1) recruits transcriptional co-activators, including histone-modifying enzymes; however, the mechanisms underlying chromatin opening remain unclear. Here, we demonstrate that HSF1 recruits the TRRAP-TIP60 acetyltransferase complex in HSP72 promoter during heat shock in a manner dependent on phosphorylation of HSF1-S419. TRIM33, a bromodomain-containing ubiquitin ligase, is then recruited to the promoter by interactions with HSF1 and a TIP60-mediated acetylation mark, and cooperates with the related factor TRIM24 for mono-ubiquitination of histone H2B on K120. These changes in histone modifications are triggered by phosphorylation of HSF1-S419 via PLK1, and stabilize the HSF1-transcription complex in HSP72 promoter. Furthermore, HSF1-S419 phosphorylation is constitutively enhanced in and promotes proliferation of melanoma cells. Our results provide mechanisms for HSF1 phosphorylation-dependent establishment of an active chromatin status, which is important for tumorigenesis.
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http://dx.doi.org/10.1038/s41467-022-32034-4 | DOI Listing |
PLoS One
January 2025
Mandel Center for Heart and Vascular Research, The Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC, United States of America.
Early events in the reprogramming of fibroblasts to cardiac muscle cells are unclear. While various histone undergo modification and re-positioning, and these correlate with the activity of certain genes, it is unknown if these events are causal or happen in response to reprogramming. Histone modification and re-positioning would be expected to open up chromatin on lineage-specific genes and this can be ascertained by studying nucleosome architecture.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
Stable inheritance of DNA N-methyladenine (6mA) is crucial for its biological functions in eukaryotes. Here, we identify two distinct methyltransferase (MTase) complexes, both sharing the catalytic subunit AMT1, but featuring AMT6 and AMT7 as their unique components, respectively. While the two complexes are jointly responsible for 6mA maintenance methylation, they exhibit distinct enzymology, DNA/chromatin affinity, genomic distribution, and knockout phenotypes.
View Article and Find Full Text PDFJ Biochem Mol Toxicol
January 2025
Department of Two Branches Outside, The First People's Hospital of Yongkang, Yongkang, China.
As the most prevalent subtype of lung cancer, lung adenocarcinoma (LUAD) is closely associated with angiogenesis, which is fundamental to its progression. ADAM8 (A disintegrin and metalloproteinase 8) is an enzyme associated with tumor invasion, while its implications in LUAD angiogenesis are a field that awaits exploration. A thorough investigation into the impacts of ADAM8 on LUAD angiogenesis could contribute to the development of therapeutic drugs for LUAD.
View Article and Find Full Text PDFJ Exp Clin Cancer Res
January 2025
Hepatology Laboratory, Solid Tumors Program, CIMA, CCUN, University of Navarra, Pamplona, Spain.
Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with limited treatment options and a poor prognosis. The critical role of epigenetic alterations such as changes in DNA methylation, histones modifications, and chromatin remodeling, in pancreatic tumors progression is becoming increasingly recognized. Moreover, in PDAC these aberrant epigenetic mechanisms can also limit therapy efficacy.
View Article and Find Full Text PDFNat Struct Mol Biol
January 2025
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
Transcription activators are said to stimulate gene expression by 'recruiting' coactivators, yet this vague term fits multiple kinetic models. To directly analyze the dynamics of activator-coactivator interactions, single-molecule microscopy was used to image promoter DNA, a transcription activator and the Spt-Ada-Gcn5 acetyltransferase (SAGA) complex within yeast nuclear extract. SAGA readily but transiently binds nucleosome-free DNA without an activator, while chromatin association occurs primarily when an activator is present.
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