RNA-directed DNA methylation (RdDM) in plants is a well-characterized example of RNA interference-related transcriptional gene silencing. To determine the relationships between RdDM and heterochromatin in the repeat-rich maize (Zea mays) genome, we performed whole-genome analyses of several heterochromatic features: dimethylation of lysine 9 and lysine 27 (H3K9me2 and H3K27me2), chromatin accessibility, DNA methylation, and small RNAs; we also analyzed two mutants that affect these processes, mediator of paramutation1 and zea methyltransferase2. The data revealed that the majority of the genome exists in a heterochromatic state defined by inaccessible chromatin that is marked by H3K9me2 and H3K27me2 but that lacks RdDM. The minority of the genome marked by RdDM was predominantly near genes, and its overall chromatin structure appeared more similar to euchromatin than to heterochromatin. These and other data indicate that the densely staining chromatin defined as heterochromatin differs fundamentally from RdDM-targeted chromatin. We propose that small interfering RNAs perform a specialized role in repressing transposons in accessible chromatin environments and that the bulk of heterochromatin is incompatible with small RNA production.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311197 | PMC |
http://dx.doi.org/10.1105/tpc.114.130427 | DOI Listing |
J Med Chem
January 2025
SANKEN, Osaka University, Mihogaoka, Ibaraki-shi, Osaka 567-0047, Japan.
Histone methylation, a crucial aspect of epigenetics, intricately involves specialized enzymes such as G9a, a histone methyltransferase (HMT) catalyzing the methylation of histone H3 lysine 9 (H3K9) and H3K27. Apart from histone modification, G9a regulates essential cellular processes such as deoxyribonucleic acid (DNA) replication, damage repair, and gene expression via modulating DNA methylation patterns. The dysregulation and overexpression of G9a are intricately linked to cancer initiation, progression, and metastasis, making it a compelling target for anticancer therapy.
View Article and Find Full Text PDFHaematologica
January 2025
The Epi-/Genome lab, Department of Hematology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen.
Not available.
View Article and Find Full Text PDFFront Immunol
January 2025
Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands.
Introduction: During the COVID-19 pandemic, major events with immune-modulating effects at population-level included COVID-19 infection, lockdowns, and mass vaccinations campaigns. As immune responses influence many immune-mediated diseases, population scale immunological changes may have broad consequences.
Methods: We investigated the impact of lockdowns, COVID-19 infection and vaccinations on immune responses in the 2000HIV study including 1895 asymptomatic virally-suppressed people living with HIV recruited between October 2019 and October 2021.
J Cancer
January 2025
Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou 510623, Guangdong, China.
Neuroblastoma is the most prevalent extracranial solid tumor among children and exhibits remarkable heterogeneity. The methylation of cytosine to form 5-methylcytosine (m5C) is the primary type of modification found in DNA and RNA. The NOL1/NOP2/sun (NSUN) family, specifically NSUN1, is responsible for the methylation process and has been shown to play a key role in cell differentiation and cancer development.
View Article and Find Full Text PDFInt J Biol Sci
January 2025
Gastric Cancer Center, Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Chemoresistance severely deteriorates the prognosis of advanced gastric cancer (GC) patients. Several studies demonstrated that (HP)-positive GC patients showed better outcomes after receiving chemotherapy than HP-negative ones. This study aims to confirm the role of HP in GC chemotherapy and to study the underlying mechanisms.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!