Ubiquityl-Histone H2B (Lys120) Recombinant Rabbit mAb (S-5698)

Ubiquityl-Histone H2B (Lys120) is a critical epigenetic mark in gene transcription activation regions. This modification is catalyzed by the E2 ubiquitin-conjugating enzyme RAD6 (UBE2A/B) in conjunction with the E3 ubiquitin ligase complex (the RNF20/RNF40 heterodimer, the human homolog of BRE1). The function of H2BK120ub is not limited to marking actively transcribed chromatin; rather, it serves as a multifunctional regulatory hub. On one hand, it directly promotes transcriptional elongation by RNA polymerase II and is essential for other important modifications (such as histone H3 methylation at lysines 4 and 79), thereby playing a central role in the hierarchical regulation of the "histone code"; on the other hand, recent structural biology studies have revealed another unique role: the modified ubiquitin molecule can stably occupy the "acidic patch" on the nucleosome surface, acting as a "gatekeeper" to prevent certain proteins from binding to the nucleosome, thus dynamically regulating chromatin interactions and accessibility. In addition, H2BK120ub is also deeply involved in critical processes such as DNA double-strand break repair, and its dysregulation is closely associated with the development and progression of various cancers, making it an important target in the fields of epigenetic regulation and cancer research.