Molecular underpinnings of Prader-Willi syndrome

摘要 Prader-Willi综合征(PWS)是一种由于失去父母亲而引起的神经遗传性疾病 染色体15q11-q13上的遗传基因。导致PWS的非典型缺失已缩小 包括SNORD116在内的一个91kb的基因座是该病的关键遗传区域。SNORD116是 由30个高度相似的C/D盒小核仁RNA(SnoRNAs)组成的簇。规范C/D盒 然而，SnoRNAs与核糖体RNA的2‘O-甲基化(2’-OMe)结合并介导其作用。 SNORD116拷贝与rRNA缺乏互补性。相反，它们被假设为修改 MRNAs或lncRNAs，但SNORD116的直接靶标尚未确定。因此，他们的 神经元的功能尚不清楚。幸运的是，每个患有PWS的人都有一个完整的 PWS关键区的表观遗传抑制拷贝，包括SNORD116，在他们的 母系等位基因。我们最近发现SNORD116的母体拷贝可以被激活 通过耗尽KRAB结构域锌指蛋白ZNF274在PWS神经元中的表达。这不仅是因为 为PWS提供一个有趣的治疗方法，但也提供了一个关键的工具来帮助 了解SNORD116是如何在神经元中调节的。这项提案的总体目标是 更好地了解PWS的分子基础。我们将确定染色质的状态 IPSCs中活性和非活性15q11-q13等位基因的染色质长程相互作用 神经元的衍生品。我们将研究通过ZNF274耗尽SNORD116的激活 组蛋白甲基转移酶抑制会影响染色质状态和长距离相互作用。 最后，我们将确定SNORD116的直接2‘-O-甲基化靶标，并确定如何 它们影响与PWS相关的差异表达基因。

ABSTRACT Prader-Willi syndrome (PWS) is a neurogenetic disorder caused by the loss of paternally inherited genes on chromosome 15q11-q13. Atypical deletions that cause PWS have narrowed the genetic region critical for the disorder to a 91kb locus including SNORD116. SNORD116 is cluster of 30 highly similar C/D box small nucleolar RNAs (snoRNAs). Canonical C/D box snoRNAs anneal to and mediate 2'O-methylation (2'-OMe) of ribosomal RNAs, however, the SNORD116 copies lack complementarity to rRNAs. Instead they are hypothesized to modify mRNAs or lncRNAs, but direct targets for SNORD116 have not been identified. Thus, their function in neurons is not known. Fortunately, every individual with PWS has an intact, but epigenetically repressed copy of the PWS critical region, including SNORD116, on their maternal allele. We have recently shown that the maternal copy of SNORD116 can be activated in PWS neurons by depleting ZNF274, a KRAB domain zinc finger protein. Not only does this suggest an intriguing therapeutic approach to PWS, but also provides a critical tool to help understand how SNORD116 is regulated in neurons. The overall goal of this proposal is to better understand the molecular underpinnings of PWS. We will determine the chromatin states and long-range chromatin interactions of active and inactive 15q11-q13 alleles in iPSCs and neuronal derivatives. We will investigate how activation of SNORD116 via ZNF274 depletion and histone methyltransferase inhibition impact the chromatin state and long-range interactions. Finally, we will identify the direct 2'-O-methylation targets of SNORD116 and determine how they influence PWS-related differentially expressed genes.