Histones are highly conserved proteins that serve as the structural scaffold for the organization of nuclear DNA into chromatin. The four core histones, H2A, H2B, H3, and H4, assemble into an octamer (2 molecules of each). Subsequently, 146 base pairs of DNA are wrapped around the octamer, forming a nucleosome, the basic subunit of chromatin. Histones are modified post-translationally by the actions of enzymes in both the nucleus and cytoplasm. These modifications regulate DNA transcription, repair, recombination, and replication. The most commonly studied modifications are acetylation, phosphorylation, methylation, and ubiquitination. These modifications can alter local chromatin architecture, or recruit trans-acting factors that recognize specific histone modifications (the \histone code\ hypothesis). The modifications occur predominantly on the N-terminal and C-terminal tails that extend beyond the nucleosome core particle. Methylation of histone H3 on Lys36 (H3K36me2/3) is tightly associated with actively transcribed genes, and this modification is found primarily within the coding region, suggesting H3K36 methylation is necessary for efficient RNA polymerase II elongation and processivity.，官网链接：https://www.sigmaaldrich.cn/product/mm/abe305s 默克 科研、开发、生产。 作为生命科学行业的全球领先供应商，我们致力于为科研、生物技术开发和生产，以及制药药物疗法开发和生产提供各类解决方案和服务。

非质量问题不退不换