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

项目摘要 最近在人类癌症和神经发育障碍中的全外显子组测序研究揭示了 编码染色质调节蛋白的基因频繁突变。具体地，编码以下亚基的基因 哺乳动物SWI/SNF ATP依赖性染色质重塑复合物（也称为mSWI/SNF或BAF 复合物）在超过20%的恶性肿瘤中受到干扰，强调了它们在维持恶性肿瘤中的关键作用。 及时和适当的基因表达。靶向mSWI/SNF家族复合物的机制 对染色质和组蛋白景观的特点，管理他们的活动仍然是未知的。确实 系统评价定义特定组蛋白景观特征对典型BAF，PBAF， 和非典型的BAF复合物的靶向和活性将代表该领域的重大进展， 大.在这里，我们的目标是：（1）确定不同的，最终形式的mSWI/SNF复合物的全基因组靶向， 人类细胞和选择的癌症相关的复杂扰动的影响;（2）定义体外 内源性纯化的mSWI/SNF亚复合物，BAF，PBAF， 和ncBAF，在野生型（WT）和突变状态;和（3）确定核心组蛋白变体的影响， 组蛋白尾部修饰对mSWI/SNF复合物核小体结合和活性的影响。综合来看，成功 这些目标的完成集中在生物化学、表观遗传学和癌症生物学的交叉点上， 构成了染色质生物学领域的一个非常及时的系列进展，并将作出重要贡献 关于mSWI/SNF复合物在一系列正常和 致癌状态考虑到开发靶向调节剂的主要障碍， 目前对mSWI/SNF复合物的研究主要在于缺乏对复合物特异性靶向和功能的生物学理解， 监管，这一建议的结果可能会提供新的方法，以有针对性的基础 破坏mSWI/SNF-染色质相互作用。

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.