Esrp regulated programs of alternative splicing in skin development and function

说明(申请人提供)：表皮和皮肤附属物执行基本的屏障功能，保护身体免受环境侮辱，并保持水-电解质平衡。组成皮肤和毛囊的细胞的发育、分化和增殖缺陷会导致许多疾病，如皮肤癌、牛皮癣、大疱性皮肤病和脱发。控制皮肤和毛囊发育的转录程序已经确定了对表皮完整性和毛发再生至关重要的过程。最近，microRNAs也成为皮肤基因表达的重要调节器。相比之下，选择性剪接(AS)在皮肤发育和功能中的作用基本上还没有研究-目前还没有关于皮肤或其附件中替代剪接因子的文献。上皮-间充质相互作用(EMIS)是表皮和毛囊形成的基础。一个重要的臂涉及间充质来源的Fgf7和/或Fgf10与成纤维细胞生长因子受体2的上皮特异性剪接异构体FGFR2-IIIb的相互作用。FGF7和FGF10与FGFR2-IIIb特异性结合，但不与间充质FGFR2-IIIc相互作用。这种定向信号通路的缺失会导致表皮和毛囊的缺陷。我的实验室鉴定了上皮细胞特异性剪接因子Esrp1和Esrp2，它们对FGFR2-IIIb剪接变异体的表达是必要和充分的 上皮细胞。我们建立了Esrp1和Esrp2基因敲除小鼠，并证明了联合使用Esrp1/Esrp2 KO是致命的，并导致表皮发育不全、毛囊数量减少和毛发稀疏。我们假设ESRP是正常的表皮和毛囊发育和功能所必需的，它通过增强上皮特异性剪接异构体的表达来实现。我们将确定皮肤和附件中特定上皮细胞群中ESRP缺失的表型，并通过以下目的确定一套全面的ESRP靶向转录本：1)确定毛囊间表皮和毛囊中与ESRP消融相关的表型。我们将定义与有条件地消融发育中和成人的表皮和毛囊中的ESRP相关的表型。2)制定ESRP调控的表皮和毛囊选择性剪接的综合方案。我们将使用高吞吐量 对敏感的微阵列进行测序(RNA-Seq)和剪接，以确定在不同的皮肤细胞群体中进行选择性剪接的全基因组计划。这些技术将与条件性缺失策略结合使用，以确定ESRP调控的靶细胞--表皮和毛囊干细胞。提出的目标构成了对皮肤发育和功能中的选择性剪接的第一次全面分析，从而为该领域引入了一种新的范式。这些研究将揭示影响皮肤的过程的新见解 发展和功能。

DESCRIPTION (provided by applicant): The epidermis and skin appendages perform essential barrier functions that protect the body from environmental insults and maintain fluid-electrolyte balance. Defects in the development, differentiation, and proliferation of the cells tht comprise the skin and hair follicles lead to numerous diseases such as skin cancer, psoriasis, bullous skin disease, and alopecia. Transcriptional programs that control skin and hair follicle development have defined processes important for epidermal integrity and hair regeneration. More recently microRNAs have also emerged as important regulators of gene expression in the skin. In contrast, the role of alternative splicing (AS) in skin development and function is essentially unstudied~ there have been no publications focused on alternative splicing factors in the skin or its appendages. Reciprocal epithelial- mesenchymal interactions (EMIs) underlie formation of the epidermis and hair follicles. One important arm involves the interaction of mesenchymal derived Fgf7 and/or Fgf10 with an epithelial-specific splice isoform of fibroblast growth factor receptor 2, Fgfr2-IIIb. Fgf7 and Fgf10 specifically interact with Fgfr2-IIIb, but not mesenchymal Fgfr2-IIIc. Abrogation of this directional signaling pathway results in defects in the epidermis and hair follicles. My lab identified the epithelial-specific splicing factors Esrp1 and Esrp2 that are both necessary and sufficient for the expression of the Fgfr2-IIIb splice variant in epithelial cells. We generated Esrp1 and Esrp2 knockout mice and demonstrate that combined Esrp1/Esrp2 KO is lethal and results in epidermal hypoplasia, reduced follicle numbers, and sparse hair. We hypothesize that the Esrps are required for normal epidermal and follicular development and function by enforcing the expression of epithelial-specific splice isoforms. We will determine the phenotypes of Esrp deletion in specific epithelial cell populations in skin and appendages and identify a comprehensive set of Esrp target transcripts through the following Aims: 1) Determine the phenotypes associated with Esrp ablation in the interfollicular epidermis and in hair follicles. We will define phenotypes associated with conditionally ablation of the Esrps in developing and adult epidermis and hair follicles. 2) Define comprehensive programs of Esrp regulated alternative splicing in the epidermis and hair follicle. We will use high throughput sequencing (RNA-Seq) and splicing sensitive microarrays to define genome-wide programs of alternative splicing in the different cell populations that populate the skin. These technologies will be used in conjunction with conditional deletion strategies to define Esrp regulated targets i the epidermis and hair follicle stem cells. The proposed aims constitute the first comprehensive analysis of alternative splicing in skin development and function, thereby introducing a new paradigm to the field. These studies will reveal novel insights into the processes that impact skin development and function.