Exploring the Mechanism of Genetic Reversion in Ichthyosis with Confetti

用五彩纸屑探索鱼鳞病基因逆转机制

• 批准号: 9539096
• 负责人: Young Lim
• 金额: $ 2.92万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-16 至 2019-09-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9539096
• 关键词: Affect; Alkylating Agents; Alleles; Animals; Area; Biochemical; Cell division; Cells; Childhood; Chromosomes; Clinical; Clonal Expansion; Color; DNA; DNA Damage; DNA Repair; DNA lesion; Data; Development; Disease; Enterobacteria phage P1 Cre recombinase; Event; Frameshift Mutation; Frequencies; Generations; Genetic; Genetic Diseases; Genetic Recombination; Genotype; Glycine; Haplotypes; Histologic; Human; Ichthyosis en confetti; Image; Individual; Induced Mutation; Inherited; Intermediate Filament Proteins; Intermediate Filaments; Ionizing radiation; Ker10 protein; Keratin; Knock-in Mouse; Lead; Lesion; Loss of Heterozygosity; Mediator of activation protein; Methods; Mitotic Recombination; Modeling; Mosaicism; Mutation; Natural Selections; Normal tissue morphology; Outcome; Pathogenicity; Pathway interactions; Patients; Phenotype; Play; Population Decreases; Proteins; Recombinants; Reporter; Resolution; Role; Self-Correction; Serine; Skin; Spottings; System; Tail; Therapeutic; Time; base; cell type; experience; gene therapy; homologous recombination; human disease; keratinocyte; mouse model; mutant; novel therapeutic intervention; pressure; recombinational repair; recruit; repaired; response; retinal rods; skin disorder; tool; two-photon

PROJECT SUMMARY / ABSTRACT Revertant mosaicism (RM) is a very rare event by which pathogenic mutations are spontaneously corrected, giving rise to areas of normal tissue. However, in ichthyosis with confetti (IWC), a severe skin disorder due to dominant mutations affecting the tail domains of intermediate filament proteins keratin 10 (KRT10) or keratin 1 (KRT1), patients develop hundreds to thousands of revertant macules of normal skin, each arising from independent events of copy-neutral loss-of-heterozygosity (CN- LOH), likely due to homology-based mitotic recombination. This dramatic increase in the frequency of an otherwise rare event provides a unique opportunity to explore mechanisms of genetic reversion, which are currently poorly understood. In IWC, revertant patches grow in number and size over time, suggesting that revertant cells acquire a selective advantage over neighboring mutant cells. Notably, mutations in other domains of KRT10 or KRT1 lead to a distinct disorder known as epidermolytic ichthyosis (EI), which features an equally severe skin phenotype without clinical or genetic evidence of RM. This implicates a unique role of the tail domain of KRT10 and KRT1 in potentially regulating DNA recombination and repair. This project aims to determine whether the frequency of genetic reversion in IWC is a direct consequence of mutant KRT10 and KRT1 effects on homology-bases recombination, and whether cellular competition between revertant and mutant clones play a role in the formation and the expansion of revertant skin. To explore these possibilities, we have developed a conditional knock-in mouse model of IWC, which recapitulates clinical and histologic features of the disease, and, more importantly, shows evidence revertant mosaicism via LOH. We will employ this murine model alongside tools to interrogate rates of LOH, DNA damage and repair, and cellular competition, to explore the mechanisms underlying the frequent genetic self-correction seen in IWC skin. Elucidating the mechanisms of genetic reversion has potential to generate new therapeutic strategies against inherited and spontaneous genetic disorders, including methods to induce or alter the rate of reversion events.

项目总结/摘要 回复突变嵌合现象（RM）是一种非常罕见的事件， 纠正，产生正常组织的区域。然而，在鱼鳞病与五彩纸屑（IWC），一个严重的 由于影响中间丝蛋白尾部结构域的显性突变引起的皮肤病 角蛋白10（KRT 10）或角蛋白1（KRT 1），患者会出现数百至数千个回复突变斑 正常皮肤，每种都由独立的拷贝中性杂合性丢失事件（CN-）引起 洛缺失），可能是由于同源性为基础的有丝分裂重组。这种频率的急剧增加 一个罕见的事件提供了一个独特的机会来探索遗传逆转的机制， 目前人们对此知之甚少。在IWC，回复突变斑块的数量和大小随着时间的推移而增长， 这表明回复突变体细胞获得了优于相邻突变体细胞的选择性优势。值得注意的是， KRT 10或KRT 1的其他结构域中的突变导致称为表皮生长因子受体的独特疾病。 鱼鳞病（EI），其特征是同样严重的皮肤表型，没有临床或遗传证据 的RM。这暗示了KRT 10和KRT 1的尾部结构域在潜在调节细胞凋亡中的独特作用。 DNA重组与修复该项目旨在确定遗传频率是否 IWC中的回复是突变体KRT 10和KRT 1对同源碱基作用的直接结果 重组，以及回复突变体和突变体克隆之间的细胞竞争是否在 回复突变体皮肤的形成和扩展。为了探索这些可能性，我们开发了 IWC的条件性基因敲入小鼠模型，其概括了IWC的临床和组织学特征， 更重要的是，显示了通过洛缺失的回复嵌合现象。我们将利用这个 小鼠模型以及询问洛缺失率、DNA损伤和修复率以及细胞凋亡率的工具。 竞争，探索IWC万国表中频繁的遗传自我校正的机制， 皮肤阐明遗传逆转的机制有可能产生新的治疗方法， 针对遗传性和自发性遗传性疾病的策略，包括诱导或改变 回复事件的发生率。