The Helios Gene in Development and Homeostasis of Skin

描述（由申请人提供）：皮肤及其附属物的动态平衡依赖于表皮的持续更新和毛囊上皮的周期性更新，这些上皮中的干细胞在整个生命周期中都存在。虽然在识别这些细胞方面已经取得了进展，但调控它们作为干细胞的分化及其后代以有序方式形成皮肤及其附属物的组成细胞类型的遗传机制仍然知之甚少。该项目考察了伊卡罗斯基因家族成员赫利俄斯在这一过程中的作用。Ikaros家族基因对造血干细胞的发育及其后代通过产生淋巴系统的谱系的后续进展至关重要。我们的初步研究表明，Helios在皮肤中表达，干扰其功能会导致皮肤发育和分化的严重缺陷。我们的假设是，太阳神的活动对皮肤及其附属物中干细胞的规范及其后代的有序分化至关重要。这个项目将测试太阳神在皮肤及其附属物发育中的作用。我们将更详细地描述太阳神的表情。在转基因小鼠的表皮和滤泡上皮中，利用Helios的一个固定等位基因与ere重组酶系一起去除Helios在不同细胞类型中的功能。这将使我们能够确定太阳神起作用的关键时期和细胞类型，并评估改变太阳神功能的近端影响。Helios功能改变的细胞将通过FACS从小鼠皮肤中表达荧光蛋白的不同细胞类型中部分纯化，并用于鉴定因Helios活性急性变化而表达变化的基因。这些基因的一个子集代表Helios调节活动的直接目标也将被确定。这些研究将影响我们对皮肤及其附属物的正常和异常发育的理解，以及该基因家族在被皮干细胞的规范和功能中的作用。

DESCRIPTION (provided by applicant): Homeostasis of the skin and its appendages relies on the continuous renewal of the epidermis and periodic renewal of the hair follicle epithelium throughout life from stem cells resident in these epithelia. While progress has been made in identifying these cells, the genetic mechanisms that regulate their specification as stem cells and the subsequent differentiation of their progeny to form the constituent cell types of the skin and its appendages in an orderly fashion remain poorly understood. This project examines the role of Helios, a member of the Ikaros gene family, in this process. The Ikaros family genes are critical to the development of hematopoietic stem cells and the subsequent progression of their progeny through the lineages that give rise to the lymphoid system. Our preliminary studies show that Helios is expressed in skin and interference with its function leads to profound defects in skin development and differentiation. It is our hypothesis that Helios activity is critical to the specification of stem cells in the skin and its appendages and to the orderly differentiation of their progeny. This project will test the role of Helios in development of the skin and its appendages. We will characterize the expression of Helios in more detail. A floxed allele of Helios will be employed in conjunction with ere recombinase lines to delete Helios function in different cell types in the epidermis and follicular epithelium of transgenic mice. This will allow us to identify critical time periods and cell types in which Helios acts and to assess the proximal effects of altering Helios function. Cells with altered Helios function will be partially purified by FACS from mice that express fluorescent proteins in different cell types in the skin and used to identify the genes whose expression changes in response to acute changes in Helios activity. A subset of these genes that represent direct targets of the regulatory activity of Helios will also be identified. These studies will impact our understanding of the normal and abnormal development of the skin and its appendages and the function of this gene family in the specification and function of stem cells of the integument.