Sequences controlling H19 Gene Imprinting

哺乳动物的一个基因子集受基因组印迹的调节，这一过程导致了不平等 这类基因的母系和父系等位基因的表达。印记基因被假设为 解释了为什么哺乳动物的正常发育需要双亲的核贡献。 此外，印记在一些人类遗传病的传播中发挥作用，包括 Beckwith-Wiedemann综合征、Silver-Russell综合征、Prader-Willi和Angelman 综合症，传递受影响基因的父母(S)的性别决定了后代是否会 发展成这种疾病。Aben-ant印记基因的表达也参与了 癌症的进展，包括肾母细胞瘤。这项建议的目的是调查- 印记基因亲本同一性建立和维持的机制。这些研究将 利用保守的H19/lgf2基因座。H19的印记，它从H19产生非编码RNA 母体来源的等位基因，以及连锁和相反印记的促进生长的Igf2基因被介导 通过2kb的印迹控制区(ICR)和共享的增强子。ICR起着甲基化的作用- 敏感的、依赖CTCF的绝缘子。当母体等位基因上没有甲基化时，绝缘体允许H19 对增强剂的独家访问。相比之下，甲基化的父系绝缘体使Igf2能够与 增强剂。本提案将从以下几个方面研究H19/lgf2印迹的机制 实验。患有BWS、散发性Wilms肿瘤和SRS的患者已被发现 人类ICR中的微缺失和表位突变以及H19和Igf2的异常印迹调控。我们 将利用这些突变建立小鼠模型和人类IPS细胞，并研究其丢失机制 印记。我们还将研究位于H19和H19之间的保守的非编码RNA的功能 IGF2和H19微RNA miR-675，使用在小鼠基因座构建的突变。我们还会另外 探讨TET1在ICR甲基化建立和消除中的作用。最后，印记 机制将在Grb10位点进行研究，这可能采用H19印迹调控的方面。 相关性(参见Infruc：tions)： 印记基因对哺乳动物的正常发育、行为和能量平衡至关重要。这 在许多人类综合征和癌症中，基因具有遗传或表观遗传突变。这些实验 在这项提案中，将在Beckwith-Wiedemann患者中模拟这些新发现的突变 综合征和Silver-Russell综合征，提供了对疾病病因的更好的理解。 项目/绩效现场(S)(如果需要额外空间，请使用

A subset of genes in mammals is regulated by genomic imprinting, a process that results in unequal expression of the maternal and paternal alleles of this class of genes. Imprinted genes are hypothesized to expiain why nuclear contributions from both parents are required for normal mammalian development. Furthermore, imprinting plays a role in the transmission of a number of human genetic diseases, including Beckwith-Wiedemann Syndrome (BWS), Silver-Russell Syndrome (SRS), Prader-Willi and Angelman Syndrome, in that the sex ofthe parent that transmits the affected gene(s) determines whether offspring will develop the disease. Aben-ant imprinted gene expression is also involved in the establishment or progression of cancers, inciuding Wilms tumors. The objective of this proposal is to investigate the- mechanism by which parental identity of imprinted genes is established and maintained. The studies will employ the conserved H19/lgf2 locus. The imprinting of H19, which produces a non-coding RNA from the maternally-derived allele, and the linked and oppositely imprinted growth-promoting Igf2 gene is mediated through the 2 kb imprinting control region (ICR) and shared enhancers. The ICR acts as a methylation- senstitive, CTCF-dependent insulator. When unmethylated on the maternal allele, the insulator allows H19 exclusive access to the enhancers. In contrast, a methylated paternal insulator enables Igf2 to engage the enhancers. This proposal will investigate the mechanism of H19/lgf2 imprinting through the following experiments. Individuals with BWS, sporadic Wilms tumors and SRS have been identified that have microdeletions and epimutations in the human ICR and aberrant imprinted regulation of H19 and Igf2. We wiil generate mouse models and human IPS cells with these mutations and study the mechanism of loss of imprinting. We will also investigate the function of a conserved non-coding RNA located between H19 and Igf2 and the H19 micro RNA, miR-675, using mutations constructed at the mouse locus. We will additionally explore the role of TET1 in the establishment and erasure of ICR methylation. Last, the imprinting mechanism will be studied at the Grb10 locus, which may employ aspects of H19 imprinted regulation. RELEVANCE (See insfruc:tions): Imprinted genes are critical for normal mammalian development, behavior and energy homeostasis. This genes have genetic or epigenetic mutations in a number of human syndromes and cancer. The experiments in this proposal will model such newly identified mutations in individuals with Beckwith-Wiedemann Syndrome and Silver-Russell Syndrome, providing a better understanding ofthe etiology ofthe disease. PROJECT/PERFORIVIANCE SITE(S) (if additional space Is needed, use