A role for Tbx18 in prostate development and adult prostate health

描述（由申请人提供）： 前列腺在哺乳动物发育中相对较晚地从尿生殖窦产生，该器官的大部分生长和分化发生在出生后。在整个前列腺发育和成年期，来自周围间充质的旁分泌信号调节前列腺上皮细胞对雄激素的响应的生长、分化和维持。进而，分化的上皮提供信号以调节间充质内的活动，并且间充质和上皮组分之间的持续、平衡的串扰对于在整个成年生活中维持健康、功能性前列腺至关重要。在识别前列腺中间充质-上皮（M-E）相互作用所涉及的信号传导途径方面已经取得了重大进展。然而，对调节前列腺发育的最早阶段或用于维持成人细胞类型和信号通路平衡的转录因子（TF）网络知之甚少。我们的初步研究确定了T-box蛋白Tbx 18是前列腺调控网络的重要成员，从前列腺发育的最早阶段开始就活跃在泌尿生殖间充质中，并在前列腺维持到成年期中继续发挥重要作用。tbx 18无效突变体在出生时死亡，使后期发育组织中的表型分析复杂化。然而，我们已经确定了Tbx 18的一个相对长寿的调节突变，称为12 Gso，我们的初步研究揭示了这些小鼠中惊人的前列腺表型。 在小鼠细胞系中使用siRNA敲低和染色质免疫沉淀（ChIP），我们已经确定了Tbx 18的直接调控靶点，其中许多在前列腺发育中发挥关键作用。然而，没有什么是已知的Tbx 18蛋白的体内目标，或控制其复杂的发育表达模式的上游转录因子。本项目的目标是（1）阐明发育中前列腺中的Tbx 18靶基因;（2）鉴定控制Tbx 18前列腺表达的调控元件和上游TF;（3）进一步表征Tbx 18突变小鼠中前列腺表型的发育时程和细胞表现，并将这些表型的发育与相互作用的TF和靶基因联系起来。在追求这些目标的过程中，我们将得到我们实验室中已有的一系列有价值的小鼠遗传和其他工具的帮助，包括转基因报告基因、条件无效（“floxed”）等位基因、12 Gso调控突变体和我们小组开发的定制Tbx 18抗体。我们假设Tbx 18是控制前列腺发育的调控网络中的关键缺失环节，在最早的发育阶段出现在UGM中，并继续在成人的基质和上皮中发挥作用。!

DESCRIPTION (provided by applicant): The prostate arises from the urogenital sinus relatively late in mammalian development, with most of the growth and differentiation of the organ occurring after birth. Throughout prostate development and into adulthood, paracrine signals from the surrounding mesenchyme regulate the growth, differentiation, and maintenance of the prostate epithelium in response to androgens. In turn, the differentiated epithelium provides signals to regulate activities within th mesenchyme and a continuing, balanced cross-talk between mesenchymal and epithelial components is critical to maintenance of a healthy, functioning prostate throughout adult life. Significant progress has been made in identifying the signaling pathways involved in mesenchymal- epithelial (M-E) interactions in the prostate. However, relatively little is known of the network of transcription factors (TFs) that regulate the earliest stages of prostate development, or that serve to maintain a balance of cell types and signaling pathways in adults. Our preliminary studies identify the T-box protein, Tbx18, as a vital member of this prostate regulatory network, active in the urogenital mesenchyme from the earliest stages of prostate development and continuing to play an important role in prostate maintenance into adulthood. Tbx18 null mutants die at birth, complicating the analysis of phenotypes in late-developing tissues. However, we have identified a relatively long-lived regulatory mutation of Tbx18, called 12Gso, and our preliminary studies have revealed a striking prostate phenotype in these mice. Using siRNA knockdown and chromatin immunoprecipitation (ChIP) in mouse cell lines, we have identified direct regulatory targets of Tbx18, many of which play key roles in prostate development. However, nothing is known about the in vivo targets of the Tbx18 protein, or of the upstream TFs that control its complex pattern of developmental expression. The goals of this project are (1) to elucidate Tbx18 target genes in the developing prostate; (2) to identify regulatory elements and upstream TFs that control Tbx18 prostate expression; and (3) to further characterize the developmental time-course and cellular manifestations of prostate phenotypes in Tbx18 mutant mice, and to tie development of these phenotypes to interacting TFs and target genes. In pursuit of these goals, we will be aided by a collection of valuable mouse genetic and other tools that are already available in our laboratory, including transgenic reporters, a conditional null ("floxed") allele, the 12Gso regulatory mutant, and a custom Tbx18 antibody developed by our group. We hypothesize that Tbx18 is a critical missing link in a regulatory network that controls prostate development, appearing in the UGM at the earliest developmental stages and continuing to act in both stroma and epithelium in adults. !