Epigenetic and transcriptional mechanisms driving human pigmentation diversity

驱动人类色素沉着多样性的表观遗传和转录机制

• 批准号: 10715498
• 负责人: Vivek Kumar Bajpai
• 金额: $ 37.33万
• 依托单位: UNIVERSITY OF OKLAHOMA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2028-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10715498
• 关键词: Affect; Anatomy; Automobile Driving; Biological Assay; CRISPR screen; Candidate Disease Gene; Cells; Chromosome Mapping; Code; Color; Control Locus; DNA; Darkness; Disease; Disease susceptibility; Enhancers; Epigenetic Process; Evolution; Gene Dosage; Gene Expression; Genes; Genetic; Genetic Screening; Genetic Transcription; Genetic study; Genome; Genome engineering; Genotype; Goals; Hair Color; Health; Human; Human Development; In Vitro; Instruction; Knowledge; Light; Location; Maps; Measurement; Melanins; Melanogenesis; Methods; Modeling; Molecular; Mus; Natural Selections; Normal Range; Phenotype; Pigmentation physiologic function; Pigments; Play; Pluripotent Stem Cells; Postdoctoral Fellow; Production; Regulator Genes; Reporter; Role; Skin Pigmentation; Transgenic Mice; Validation; Variant; Work; differential expression; epigenomic profiling; experimental study; genome wide association study; genome-wide; human population study; insight; melanocyte; mouse model; novel; programs; skin color; skin disorder; stem cell differentiation; trait; transcription factor

Melanin is the key determinant of human pigmentation that has evolved under natural selection and has led to diversification of human skin color. Importantly, the number of melanin-producing-melanocytes and their anatomical location do not vary among humans, only varying melanogenesis determines the human pigmentation diversity. Our long-term goal is to build a comprehensive understanding of the epigenetic and transcriptional machinery that dictate precise human melanogenesis gene expression programs that governs normal-range human pigmentation variation and disease susceptibility. The key insights about human melanogenesis have come from mapping genes involved in hypo- and hyper pigmentation diseases, Genome- wide Association Studies (GWAS) of normal-range skin and hair color variation in human populations and genetic studies on mouse coat color. Nonetheless, current genetic knowledge can explain only a fraction of skin color variation in humans suggesting that many loci controlling pigmentation remain unknown. By conducting a genome-wide CRISPR screen, PI has uncovered novel candidate genes driving human pigmentation. Among the novel pigmentation genes identified, we found that KLF transcription factors are differentially expressed in light and dark colored human melanocytes and play an antagonistic role in melanogenesis in a gene dosage dependent manner. We will investigate the cellular and molecular mechanisms of these closely related factors to understand their roles in human pigmentation variation. Consistent with other human phenotypes, we hypothesize that most DNA variants driving normal-range human pigmentation and skin disease susceptibility may lie in non-protein-coding regions of genome. We will map the cis-regulatory landscape of melanocytes from diverse color humans by performing unbiased epigenomic profiling to uncover putative enhancers with divergent gene regulatory activity. We will prioritize the candidate divergent enhancers for functional analysis by focusing on loci that have either previously been associated with skin color GWAS studies or overlap with novel melanogenesis genes identified by our genome-wide genetic screen. Through genetic perturbation studies we will confirm whether cis-regulatory changes affect gene expression quantitatively. Building on PI’s postdoctoral work, over the next five years, the lab will combine diverse approaches to understand the genotype-to-phenotype connection in human skin pigmentation variation. These approaches include pluripotent stem cell differentiation models that recapitulate human melanogenesis in vitro, genome-engineering, massively parallel reporter assays, single-cell profiling methods, quantitative melanin measurements, and validation experiments in transgenic mouse models. Through our studies on a highly quantifiable trait such as melanin, we will provide insights into how genotypic variation encoded in genome give rise to differences in gene expression and leads to phenotypic divergence within human species, which has implication for human development, health and disease.

黑色素是人类色素沉着的关键决定因素，它在自然选择下进化并导致 人类肤色的多样化。重要的是，产生黑色素的黑素细胞的数量及其 人体的解剖位置并不不同，只有不同的黑色素生成决定了人体的 色素沉着多样性。我们的长期目标是建立对表观遗传和 转录机制决定精确的人类黑素生成基因表达程序 正常范围的人类色素沉着变化和疾病易感性。关于人类的重要见解 黑色素生成来自绘制色素沉着不足和色素沉着过度疾病相关基因的图谱，基因组- 人类正常范围皮肤和头发颜色变异与遗传的广泛关联研究 (GWAS) 对小鼠皮毛颜色的研究。尽管如此，目前的遗传知识只能解释一小部分肤色 人类的变异表明许多控制色素沉着的基因座仍然未知。通过进行 通过全基因组 CRISPR 筛选，PI 发现了驱动人类色素沉着的新候选基因。之中 在鉴定出的新色素沉着基因中，我们发现 KLF 转录因子在 浅色和深色人类黑色素细胞，并在基因剂量的黑色素生成中发挥拮抗作用 依赖方式。我们将研究这些密切相关因素的细胞和分子机制 了解它们在人类色素沉着变化中的作用。与其他人类表型一致，我们 假设大多数 DNA 变异导致正常范围的人类色素沉着和皮肤病易感性 可能位于基因组的非蛋白质编码区域。我们将绘制黑素细胞的顺式调控图谱 通过进行公正的表观基因组分析来发现具有不同颜色的假定增强子 基因调控活性。我们将通过重点关注候选不同增强子的优先级来进行功能分析 先前与肤色 GWAS 研究相关或与新发现重叠的位点 通过我们的全基因组遗传筛选鉴定出黑色素生成基因。通过遗传扰动研究我们 将定量确认顺式调控变化是否影响基因表达。以PI博士后为基础 在未来五年的工作中，实验室将结合多种方法来了解基因型到表型 人类皮肤色素沉着变化的联系。这些方法包括多能干细胞分化 体外重现人类黑色素生成的模型、基因组工程、大规模并行报告分析、 单细胞分析方法、定量黑色素测量和转基因验证实验 鼠标模型。通过对黑色素等高度可量化特征的研究，我们将提供以下见解： 基因组中编码的基因型变异如何引起基因表达的差异并导致表型 人类物种内部的差异，对人类发展、健康和疾病具有影响。