A role for Tbx18 in prostate development and adult prostate health

描述(由申请人提供)： 在哺乳动物的发育中，前列腺起源于泌尿生殖窦较晚，大部分器官的生长和分化发生在出生后。在整个前列腺发育和成年过程中，来自周围间充质的旁分泌信号调节前列腺上皮的生长、分化和维持，以响应雄激素。反过来，分化的上皮细胞提供信号来调节间充质内的活动，间充质和上皮成分之间持续、平衡的串扰对于成年后维持健康、功能正常的前列腺至关重要。在识别前列腺间充质-上皮(M-E)相互作用的信号通路方面已经取得了重大进展。然而，对转录因子网络的了解相对较少，转录因子网络调节前列腺发育的早期阶段，或在成人中维持细胞类型和信号通路的平衡。我们的初步研究发现，T-box蛋白TBX18是这一前列腺调节网络的重要成员，从前列腺发育的最早阶段起就活跃在泌尿生殖间质中，并在前列腺癌的成年期维持中继续发挥重要作用。TBX18缺失突变体在出生时死亡，使后期发育组织的表型分析复杂化。然而，我们已经确定了TBX18的一个相对长寿的调节性突变，称为12Gso，我们的初步研究显示，在这些小鼠中有一种惊人的前列腺表型。利用小鼠细胞系中的siRNA敲除和染色质免疫沉淀(CHIP)，我们已经确定了TBX18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，对于TBX18蛋白的体内靶点，或者控制其复杂的发育表达模式的上游转录因子，我们一无所知。本项目的目标是(1)阐明TBX18在发育中的前列腺中的靶基因；(2)确定控制TBX18前列腺癌表达的调控元件和上游转录因子；(3)进一步表征TBX18突变小鼠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转录因子和靶基因的相互作用联系起来。为了实现这些目标，我们将获得我们实验室已有的一系列有价值的小鼠遗传学和其他工具的帮助，包括转基因记者、条件性空(“牙线”)等位基因、12Gso调节突变体，以及我们团队开发的定制TBX18抗体。我们假设，在控制前列腺发育的调控网络中，TBX18是一个关键的缺失环节，在最早的发育阶段出现在UGM中，并继续在成人的间质和上皮中发挥作用。好了！

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. !