Structure-activity relationships governing mammalian SWI/SNF chromatin remodeling activity as a function of chromatin state

项目总结 最近人类癌症和神经发育障碍的全外显子组测序研究已经揭开了面纱 染色质调节蛋白编码基因的频繁突变。具体来说，编码亚基的基因 哺乳动物SWI/SNF-ATP依赖的染色质重塑复合体(又称mSWI/SNF或BAF 复合体)在超过20%的恶性肿瘤中受到干扰，这突显了它们在维持 及时、适当的基因表达。MSWI/SNF家族复合体的靶向机制 关于染色质和支配其活动的组蛋白景观的特征仍不清楚。事实上，一个 系统评价确定了特定的组蛋白景观特征对典型BAF、PBAF、 而非规范的BAF复合体的靶向和活性将代表着该领域的重大进步- 大号的。在这里，我们的目标是：(1)确定不同的最终形式的mSWI/SNF复合体在全基因组范围内的靶向 人类细胞和选定的癌症相关复杂扰动的影响；(2)定义体外 内源性纯化的mSWI/SNF亚复合体、BAF、PBAF、 和ncBAF，在野生型(WT)和突变状态下；以及(3)确定核心组蛋白变体和 组蛋白尾部修饰对mSWI/SNF复合体核小体结合和活性的影响。总而言之，成功 以生物化学、表观遗传学和癌症生物学为中心的这些目标的完成，将 构成了染色质生物学领域一系列非常及时的进展，并将做出重要贡献 关于mSWI/SNF复合体在正常和 致癌状态。鉴于靶向调节剂发展的一个主要障碍是 MSWI/SNF复合体的问题在于缺乏对复合体特异性靶向和功能的生物学理解 监管，这项提议的结果可能为有针对性的新方法提供基础 MSWI/SNF-染色质相互作用的中断。

PROJECT SUMMARY Recent whole-exome sequencing studies in human cancer and neurodevelopmental disorders have unmasked frequent mutations in genes encoding chromatin regulatory proteins. Specifically, genes encoding subunits of the mammalian SWI/SNF ATP-dependent chromatin remodeling complexes (also called mSWI/SNF or BAF complexes) are perturbed in over 20% of malignancies, underscoring their critical roles in the maintenance of timely and appropriate gene expression. The mechanisms by which mSWI/SNF family complexes are targeted on chromatin and the features of the histone landscape that govern their activities remain unknown. Indeed, a systematic evaluation defining the contributions of specific histone landscape features to canonical BAF, PBAF, and non-canonical BAF complex targeting and activity would represent a significant advancement in the field at- large. Here we aim to: (1) Determine the genome-wide targeting of distinct, final-form mSWI/SNF complexes in human cells and the impact of select cancer-associated complex perturbations; (2) Define the in vitro nucleosome remodeling and ATPase activities of endogenously-purified mSWI/SNF subcomplexes, BAF, PBAF, and ncBAF, in wild-type (WT) and mutant states; and (3) Determine the impact of core histone variants and histone tail modifications on mSWI/SNF complex nucleosome binding and activity. Taken together, successful completion of these aims centered at the intersection of biochemistry, epigenetics, and cancer biology, will constitute a highly timely series of advances in the field of chromatin biology, and will contribute important knowledge regarding the mechanism of targeting of mSWI/SNF complexes across a range of both normal and oncogenic states. Given that a major impediment to the development of on-target modulatory agents of mSWI/SNF complexes lies in the lack of biological understanding of complex-specific targeting and functional regulation, the results of this proposal are likely to provide the basis for new approaches toward targeted disruption of mSWI/SNF-chromatin interactions.