Defining USP22 Functions During Mammalian Development

项目摘要 USP22泛素特异性蛋白水解酶的过度表达与多种类型肺癌患者预后不良有关 耐药癌症，导致其被指定为“癌症死亡”基因标志的成员。 然而，USP22在正常细胞中的功能还没有很好的定义，所以还不清楚这种酶是如何 有助于癌症的形成或进展。USP22是脱泛素化模块的催化亚单位 (DUB)在高度保守的SAGA复合体中，它调节基因过程中的多个步骤 抄写。在上一个资助期，我们培育了USP22缺失小鼠，以进一步确定其在体内的功能， 我们发现在胎盘发育过程中，USP22在胎儿血管发育中起着重要作用 迷宫。RNA-SEQ揭示了转化生长因子-β和受体酪氨酸激酶(RTK)通路(例如c-Met/HGFR， Errb2和PDGFR)在USP22突变胎盘中表达下调。这些途径不仅是必不可少的 对于正常的胎盘发育和肿瘤的发生，以及对TCGA数据的检查显示这些 在过度表达USP22的肿瘤中，通路被上调。我们假设USP22规定了这些 控制正常细胞生长和行为的途径以及USP22表达的异常 导致与疾病相关的信号通路异常。来检验这一假设并定义 Usp22突变体中转化生长因子-β和RTK信号变化的机制基础，我们将使用小鼠和细胞 带有USP22到1的条件NULL、‘FLOXED’等位基因或条件过表达等位基因)定义特定 受USP22缺失影响的胎盘细胞谱系定义了USP22和3的直接分子靶点。 确定USP22的过度表达是否足以驱动小鼠异常的转化生长因子-β1或RTK信号。 这些研究将为USP22在信号、发育和 疾病。从长远来看，我们的发现将为子痫前期和癌症的病因学提供新的见解。 它们可能为治疗或预防这些疾病提供新的途径。

Project Summary Overexpression of the USP22 ubiquitin specific protease is linked to poor patient outcome in multiple types of therapy resistant cancers, leading to its designation as a member of a `death from cancer' gene signature. However, the functions of USP22 in normal cells are not well defined, so it is not clear how this enzyme contributes to cancer formation or progression. USP22 is the catalytic subunit of the deubiquitination module (DUB) within the highly conserved SAGA complex, which regulates multiple steps in the process of gene transcription. In the last funding period, we generated USP22 null mice to further define its functions in vivo, and we discovered a role for USP22 in development of fetal vasculature during development of the placental labyrinth. RNA-seq reveals that TGF-beta and receptor tyrosine kinase (RTK) pathways (e.g. c-Met/HGFR, Errb2, and PDGFR) are down regulated in USP22 mutant placentas. These pathways are essential not only for normal placental development but also for tumorigenesis, and examination of TCGA data reveals that these pathways are up regulated in tumors that overexpress USP22. We hypothesize that USP22 regulates these pathways to control the growth and behavior of normal cells, and that aberrations in USP22 expression contributes to signaling pathway aberrations associated with disease. To test this hypothesis and to define the mechanistic basis of changes in TGF-beta and RTK signaling in Usp22 mutants, we will use mice and cells bearing a conditional null, `floxed' allele or a conditional overexpressing allele of USP22 to 1) Define specific cell lineages in the placenta affected by USP22 loss 2) Define direct molecular targets of USP22 and 3) Determine whether USP22 overexpression is sufficient to drive abnormal TGF-beta1 or RTK signaling in mice. These studies will establish new paradigms for the functions of USP22 in signaling, in development, and in disease. In the longer term, our findings will provide new insights to the etiology of preeclampsia and cancer, and they may provide new avenues for treatment or prevention of these conditions.