Patty Benjamin, Jordan Cailin, Lardo Santana, Troy Kris, Hainer Sarah
University of Pittsburgh.
Res Sq. 2024 Aug 27:rs.3.rs-4824795. doi: 10.21203/rs.3.rs-4824795/v1.
The histone variant H3.3 acts in coordination with histone posttranslational modifications and other chromatin features to facilitate appropriate transcription. Canonical histone H3 and histone variant H3.3 are post-translationally modified with the genomic distribution of these marks denoting different features and with more recent evidence suggesting that these modifications may influence transcription. While the majority of posttranslational modifications occur on histone tails, there are defined modifications within the globular domain, such as acetylation of H3K122/H3.3K122. To understand the function of the residue H3.3K122 in transcriptional regulation, we attempted to generate H3.3K122A mouse embryonic stem (mES) cells but were unsuccessful. Through multi-omic profiling of mutant cell lines harboring two or three of four H3.3 targeted alleles, we have uncovered that H3.3K122A is neomorphic and results in lethality. This is surprising as prior studies demonstrate H3.3-null mES cells are viable and pluripotent, albeit with reduced differentiation capacity. Together, these studies have uncovered a novel dependence of a globular domain residue of H3.3 for viability and broadened our understanding of how histone variants contribute to transcription regulation and pluripotency in mES cells.
组蛋白变体H3.3与组蛋白翻译后修饰及其他染色质特征协同作用，以促进适当的转录。经典组蛋白H3和组蛋白变体H3.3会发生翻译后修饰，这些修饰的基因组分布表示不同的特征，并且最近有证据表明这些修饰可能影响转录。虽然大多数翻译后修饰发生在组蛋白尾部，但在球状结构域内也存在特定的修饰，例如H3K122/H3.3K122的乙酰化。为了了解H3.3K122残基在转录调控中的功能，我们试图生成H3.3K122A小鼠胚胎干细胞（mES），但未成功。通过对携带四个H3.3靶向等位基因中的两个或三个的突变细胞系进行多组学分析，我们发现H3.3K122A具有新的表型并导致致死性。这令人惊讶，因为先前的研究表明H3.3基因敲除的mES细胞是有活力的且具有多能性，尽管其分化能力有所降低。总之，这些研究揭示了H3.3球状结构域残基对细胞活力的新依赖性，并拓宽了我们对组蛋白变体如何促进mES细胞转录调控和多能性的理解。
