Regulation of the melanocyte lineage by the AP2 transcription factor family

AP2 转录因子家族对黑素细胞谱系的调节

• 批准号: 8506691
• 负责人: Robert Aaron Cornell
• 金额: $ 32万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-25 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8506691
• 关键词: Alleles; Automobile Driving; Back; Binding; Binding Sites; Biochemical; Biological Assay; Biological Models; Biology; Branchio-Oculo-Facial Syndromes; Cell Culture Techniques; Cell Differentiation process; Cell Maintenance; ChIP-seq; Congenital Megacolon; DNA Binding; Data; Development; Diagnosis; Dimerization; Dominant-Negative Mutation; Dopachrome isomerase; Elements; Embryo; Embryonic Development; Enhancers; Etiology; Event; Family; Family member; Functional RNA; Gene Expression; Genes; Genetic; Genetic Epistasis; Gray unit of radiation dose; Hair; Homeostasis; Human; Knock-out; Knowledge; Life; Light; Mammals; Methods; Modeling; Molecular Genetics; Molecular Profiling; Mus; Mutation; Neural Crest; Oculocutaneous Albinism; Outcome; Output; Patients; Phenotype; Physiology; Piebaldism; Pigmentation Disorders; Pigmentation physiologic function; Play; Positioning Attribute; Process; Property; Recovery; Regulation; Regulatory Element; Reporter; Research; Risk; Role; Severities; Skin Cancer; Stem Cell Factor; Stem cells; System; TFAP2A gene; Testing; Tietze' s Syndrome; Tissues; Transcription Factor 3; Transcription Factor AP-2 Alpha; Transcriptional Regulation; Variant; Waardenburg syndrome; Work; Zebrafish; adult stem cell; base; cell type; craniofacial; design; developmental disease; embryo tissue; genetic regulatory protein; in vitro testing; in vivo; interest; knock-down; melanocyte; microphthalmia-associated transcription factor; mutant; novel; novel therapeutics; overexpression; paralogous gene; precursor cell; premature; prevent; promoter; protein function; public health relevance; stem cell differentiation; transcription factor; ultraviolet irradiation

DESCRIPTION (provided by applicant): Transcription factors are central players in the regulatory networks that control differentiation in all types of precursor cells and stem cells. Itis well known that transcription factors regulate gene expression, but it is unclear how they regulate differentiation. For instance, in some cases a given transcription factor promotes cell differentiation in one context, and prevents it in another. Melanocytes are an ideal model cell type to explore cellular developmental events because their differentiation is easily scored, they are not essential for life, and loss of melanocyte stem cells in mammals is readily apparent by the consequent hair graying. Moreover, mutations in genes encoding transcription factors and other regulatory molecules cause developmental disorders of pigmentation (e.g., Hirschsprung's disease, Tietz syndrome, Waardenburg syndrome types I- IV, piebaldism). Our long-term objective is to understand the regulatory network governing developmental events in the melanocyte lineage. Here we focus on the transcription factor Activator Protein 2 family (TFAP2A-E). TFAP2A appears to prevent differentiation of melanocyte stem cells, because dominant mutations in TFAP2A cause Branchio Oculo Facial Syndrome (BOFS), which features premature hair graying. By contrast, TFAP2A and its paralog TFAP2E appear to promote differentiation of embryonic melanocytes, as shown by our work in zebrafish. We hypothesize that within melanocyte precursors, TFAP2 proteins function redundantly, and in parallel with microphthalmia-associated transcription factor (MITF), a central regulator of melanocyte biology, to activate genes that effect melanocyte differentiation. To test this model we will conduct knock-down/add-back studies in zebrafish, generate appropriate tissue- specific double mutants in mice, and conduct functional analysis of the promoter of a gene mutually activated by TFAP2 proteins and MITF in cultured in human melanocytes. Next we will examine how TFAP2A functions to maintain melanocyte stem cells (MSC). We hypothesize that in this context, the key function of TFAP2A is to activate KIT. To test this notion we will use zebrafish again for epistasis tests, examine hair graying in a mouse with neural-crest-specific deletion of TFAP2A, and assess functional properties of TFAP2A variants associated with hair graying in BOFS. Finally, we will conduct systematic analyses of potential regulators of TFAP2A expression in melanocytes, and a global analysis of TFAP2A transcriptional targets in melanocytes, which together will position TFAP2A into a regulatory network in melanocytes. Our studies will shed light on novel genetic and molecular networks that underlie normal and pathological development of melanocytes. The new knowledge generated from this work will be of value specifically in the etiology of Waardenburg syndrome and BOFS. More generally, it will illuminate the transcriptional regulation of differentiation in a tractable model cell type.

描述(申请人提供)：转录因子是控制所有类型的前体细胞和干细胞分化的调控网络的中心角色。众所周知，转录因子调节基因表达，但不清楚它们是如何调节分化的。例如，在某些情况下，给定的转录因子在一种情况下促进细胞分化，在另一种情况下阻止细胞分化。黑素细胞是研究细胞发育事件的理想模型细胞类型，因为它们的分化很容易得分，它们不是生命所必需的，而且哺乳动物中黑素细胞干细胞的丢失很容易通过随之而来的头发灰白而明显。此外，编码转录因子和其他调节分子的基因突变会导致色素沉着的发育障碍(例如，先天性巨结肠、蒂茨综合征、瓦登堡综合征I-IV型、花斑病)。我们的长期目标是了解控制黑素细胞谱系发育事件的调控网络。在这里，我们重点介绍转录因子激活蛋白2家族(TFAP2A-E)。TFAP2A似乎可以阻止黑素细胞干细胞的分化，因为TFAP2A的显性突变会导致Branchio Oculo Faces综合征(BofS)，其特征是头发过早变白。相反，TFAP2A及其类似的TFAP2E似乎促进了胚胎黑素细胞的分化，正如我们在斑马鱼上的工作所表明的那样。我们假设，在黑素细胞前体中，TFAP2蛋白的功能是冗余的，并且与黑素细胞生物学的中央调节因子小眼球相关转录因子(MITF)平行地激活影响黑素细胞分化的基因。为了测试这个模型，我们将在斑马鱼中进行击倒/加回研究，在小鼠中产生适当的组织特异性双重突变体，并在培养的人类黑素细胞中对TFAP2蛋白和MITF共同激活的基因的启动子进行功能分析。接下来，我们将研究TFAP2A如何发挥维持黑素细胞干细胞(MSC)的功能。我们推测，在这种情况下，TFAP2A的关键功能是激活KIT。为了测试这一概念，我们将再次使用斑马鱼进行上位性测试，检查具有神经脊特异性TFAP2A缺失的小鼠的头发白化，并评估与BofS中头发白化相关的TFAP2A变体的功能特性。最后，我们将对黑素细胞中TFAP2A表达的潜在调控因子进行系统分析，并对黑素细胞中TFAP2A转录靶标进行全球分析，这将共同将TFAP2A定位为黑素细胞中的调节网络。我们的研究将揭示新的遗传和分子网络，这些网络是黑素细胞正常和病理发育的基础。这项工作产生的新知识将对Waardenburg综合征和BofS的病因学特别有价值。更广泛地说，它将阐明在一个易处理的模型细胞类型中分化的转录调节。