Ubiquityl-Histone H3 (Lys18) Recombinant Rabbit mAb (S-4790)

Ubiquityl-Histone H3 (Lys18) refers to an epigenetic mark characterized by ubiquitination of histone H3 at its 18th lysine residue, representing a relatively recently recognized regulatory mode among histone post-translational modifications. This modification is catalyzed by specific E3 ubiquitin ligases (such as RNF168 and RNF20), which covalently attach ubiquitin molecules to the K18 site of H3, while deubiquitinases (such as USP51) can reverse it. Unlike classical histone ubiquitination sites (e.g., K120/K123 on H2B), H3K18 ubiquitination is primarily enriched at gene promoter regions and transcription elongation regions, and its function is closely associated with transcriptional activation—studies have shown that H3K18 ubiquitination promotes RNA polymerase II recruitment and promoter escape, thereby enhancing downstream gene expression. Additionally, this modification plays an important role in DNA damage repair: upon DNA double-strand breaks, RNF168-mediated H3K18 ubiquitination cooperates with H2A/H2AX ubiquitination to recruit repair proteins (such as 53BP1 and BRCA1) to the damage sites, regulating the choice of repair pathways. Under pathological conditions, aberrant changes in H3K18 ubiquitination levels are associated with various cancers (e.g., breast cancer, prostate cancer, colorectal cancer), neurological disorders (e.g., Huntington's disease), and developmental defects, potentially promoting tumor initiation and progression by affecting the transcription of oncogenes or tumor suppressor genes. In epigenetic research and clinical translation, detecting Ubiquityl-Histone H3 (Lys18) helps elucidate the mechanisms of gene transcription regulation, DNA damage response, and tumorigenesis, and provides a potential biomarker for the development of epigenetic drugs targeting the ubiquitination pathway.