BWS and Embryonal Tumor Suppressor Genes on 11p15

Beckwith-Wiedemann综合征(BWS)是由一种易患癌症的疾病引起的范例 表观遗传学机制，并作为一般理解癌症表观遗传学的模型。病人 患有BW的儿童患Wilms肿瘤(WT)和其他胚胎癌症的风险增加800倍， 以及出生缺陷，包括体型增大、器官过度生长和中线闭合缺陷。我们之前 将BWS定位于11个p15区域，其中包含一个在WT和普通成人中丢失的未知WT基因(WT2) 癌症。在这个荣誉奖项的头31年半里，我们完成了第一个表观表现型 对任何疾病的研究表明，BWS是一种带有H19和IGF2基因的邻近基因综合征 导致癌症，以及LIT1和p57^p2导致出生缺陷。我们首次将任何混乱和 辅助生殖技术(ART)，显示与BWS中LIT1的表观遗传学变化有关。 我们还鉴定了BWS中第一个染色体微缺失，鉴定了控制BWS的印记元件 T、pz等基因，以及LIT1中一种新的染色质绝缘子。最后，我们确定了几个潜在的 关键的新基因，包括定位于线粒体的沉默信息调节因子(SIRT3)和一个 候选WT2基因。这个先前未被发现的印记基因编码了一种定位于 核仁，它的表达在WT中丢失，伴随杂合性丢失或印迹丢失，它抑制 WT等肿瘤的生长。 在优点扩展中，我们将确定家族性BW和监管机构中的额外微缺失 其中的元素和基因。我们将研究ART诱导的表观遗传缺陷的机制。 通过小鼠配子的体外培养和受精，以及表观遗传缺陷对小鼠配子发育的影响 子代的癌症发病率。我们将研究30%的BWS患者的分子基础 甲基化改变，以及特发性半肥厚患者，使用新的染色质免疫沉淀- 在当前赠与期内制定的技术办法。我们将研究基因与基因之间的关系 家系的表观遗传型。我们将继续在BWS中识别新的基因和调控元件，使用 表观基因组学和功能学方法，包括假定的p57Kip2增强子和低血糖基因- 米娅。我们将对候选WT2基因和另一基因identi进行遗传和功能分析。 在当前的授权期内，这可能会调解LIT1的功能。这些研究将包括活体小鼠 模型，核仁蛋白结合的生化研究，以及结合伙伴的鉴定，包括 与LIT1结合的新型绝缘体蛋白。这项工作应该继续提供开创性的见解 癌症的遗传学和表观遗传学，以及环境和发育失误在癌症中的作用 表观遗传学的破坏，对理解人类癌症的机制具有广泛的意义。

Beckwith-Wiedemann Syndrome (BWS) is the paradigm of cancer-predisposing disorders caused by an epigenetic mechanism, and it serves as a model for a general understanding of cancer epigenetics. Patients with BWS have an 800-fold increased risk of Wilms tumor (WT) and other embryonal cancers of childhood, as well as birth defects including increased size, organ overgrowth, and midline closure defects. We earlier mapped BWS to a region of 11 p15 containing an unidentified WT gene (WT2) lost in WT and common adult cancers. In the first 31/2 years of this MERIT award, we have performed the first epigenotype-phenotype study of any disorder, showing that BWS is a contiguous gene syndrome with the genes H19 and IGF2 causing cancer, and LIT1 and p57^p2 causing birth defects. We made the first link between any disorder and assisted reproductive technology (ART), showing an association with epigenetic changes in LIT1 in BWS. We also identified the first chromosomal microdeletion in BWS, identifying an imprinting element controlling T^pz and other genes, and a novel chromatin insulator in LIT1. Finally, we identified several potentially critical novel genes, including a silence information regulator (SIRT3) localized to mitochondria, and a candidate WT2gene. This previously unappreciated imprinted gene encodes a protein localized to the nucleolus, its expression is lost in WT with loss of heterozygosity or loss of imprinting, and it suppresses the growth of WT and other tumors. In the MERIT extension, we will identify additional microdeletions in familial BWS and the regulatory elements and genes within them. We will investigate the mechanism of ART-induced epigenetic defects in BWS through in vitro culture and fertilization of mouse gametes, and the effect of epigenetic defects on cancer incidence in the offspring. We will investigate the molecular basis of the 30% of BWS patients without methylation changes, as well as idiopathic hemihypertrophy patients, using new chromatin immunoprecipita- tion approaches developed in the current grant period. We will investigate the relationship between genotype and epigenotype in families. We will continue to identify new genes and regulatory elements in BWS, using epigenomic and functional approaches, including a putative enhancer for p57KIP2 and a gene for hypoglyce- mia. We will perform genetic and functional analyses of the candidate WT2 gene and another gene, identi- fied in the current grant period, that may mediate LIT1 function. These studies will include in vivo mouse models, biochemical studies of nucleolar protein binding, and identification of binding partners, including a novel insulator protein that binds to LIT1. This work should continue to provide pioneering insights into the genetics and epigenetics of cancer, as well as the role of environmental and developmental miscues in epigenetic disruption, with broad implications for understanding the mechanism of human cancer.