Cell regulation by oncogenes in Development

发育过程中癌基因的细胞调节

• 批准号: 6950982
• 负责人: xianyu s Hou
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6950982
• 关键词: Drosophilidae; JAK kinase; arthropod genetics; biological signal transduction; developmental genetics; embryogenesis; gene mutation; genetic mapping; genetic models; genetic regulation; genetic screening; invertebrate embryology; oncogenes; protein structure function; suppressor mutations; transforming growth factors

Using the Drosophila system, our research goal is to understand cell biology events elicited by cancer-causing genes. My group is focusing on the following two projects: (1) the JAK/STAT signal transduction pathway in Drosophila development and tumor formation; and (2) the epithelial cell sheet movement during Drosophila embryonic dorsal closure. I. The Drosophila JAK/STAT signal transduction pathway The JAK/STAT cascade has emerged as an essential reutilized facet of vertebrate signaling through a large number of cytokines and growth factors. Both decreases and increases in activity of this signaling pathway have severe consequences. Constitutive activation of JAKs and or STATs is correlated with several oncogenic transformations. In 1996, as a postdoctoral fellow in Dr. Norbert Perrimon's laboratory, I isolated the Drosophila STAT mutation (Hou et al., 1996). Overexpression of upd (pGMR-upd), the ligand of the Drosophila JAK/STAT signal transduction pathway, in the fly eye resulted in large deformed eyes. In a genetic screen for suppressors of the abnormal eye phenotype, we identified a receptor (named master of marelle or mom) of the JAK/STAT signal transduction pathway (Chen et al., 2002). In our recent GLC screen, we took advantage of the available complete Drosophila genomic sequence. We first performed a P element-mediated gene disruption screen. By examining over 50,000 mutant lines, we isolated 2,500 single P-insertion lethal mutants. Sequences flanking >2300 insertions were determined that identify 850 different genes or ESTs (Oh et al., 2002). We then performed GLC assays for 600 selected genes whose mutations had not been studied prior to our P-element screen. From the GLC screen, several new genes, "hop-like" genes, have been identified that appear to be part of the JAK/STAT pathway. The Drosophila cyclin-dependent kinase 4 (Cdk4) is among these new genes. We demonstrated that Cyclin D-Cdk4 (and also Cyclin E-Cdk2) binds and regulates STAT92E protein stability (Chen et al., 2003). We further showed that the JAK/STAT signaling and CycD-Cdk4 signaling synergistically regulate melanotic tumor formation. In the eye, the CycD-Cdk4 signaling prevents cell differentiation and the JAK/STAT signaling promotes cell proliferation; collaboration between these two signals leads to the eye's "tumor-like" outgrowth. We have cloned two SOCS genes from Drosophila, socs44A and socs60E. Our results suggest that SOCS60E specifically down-regulates the JAK/STAT signaling and SOCS44A mostly regulates other signalings. II. The epithelial cell sheet movement during Drosophila embryonic dorsal closure In many epithelial-derived cancers, signals will eventually cause cell polarity changes and breakdown of cell junctions, which are the initial steps of tumor metastasis. Drosophila embryonic dorsal closure (DC) mimics these events and provides an excellent system to understand the molecular mechanisms of these processes. DC is also being used as a model system to study wound healing. In DC, actin dynamics at the leading edge are preceded by a polarization of the dorsal-most epidermal cells associated with a reorganization of the cytoskeleton. In 1997, we discovered the Drosophila homologue of the mammalian proto-oncogene c-Jun gene (Djun) as a central regulator of the DC process (Hou et al., 1997). We recently characterized another gene that regulates the DC process, connector of kinase to AP-1 (cka). cka encodes a protein containing several protein-protein interaction domains. CKA forms a complex with HEP (DJNKK), BSK (DJNK), DJUN, and DFOS. The complex activates BSK kinase, which phosphorylates and activates DJUN and DFOS. CKA represents a novel molecule regulating AP-1 activity by organizing a molecular complex of kinases and transcription factors (Chen et al., 2002).

使用果蝇系统，我们的研究目标是了解由癌症引起的基因引起的细胞生物学事件。我的小组关注以下两个项目：（1）果蝇发育和肿瘤形成中的JAK/STAT信号转导途径； （2）果蝇胚胎背侧闭合期间的上皮细胞片运动。 I.果蝇jak/stat信号转导途径 通过大量的细胞因子和生长因子，JAK/STAT级联反应已成为脊椎动物信号的必不可少的小方面。这两种信号传导途径的活性都会下降和增加都有严重的后果。 JAKS和 /或统计数据的组成型激活与几种致癌转化有关。 1996年，作为诺伯特·佩里蒙（Norbert Perrimon）博士实验室的博士后研究员，我隔离了果蝇统计突变（Hou等，1996）。 在苍蝇眼中，果蝇jak/stat信号转导途径的upd（pGMR-upd）的过表达导致眼睛大变形。在异常眼表型抑制因子的遗传筛选中，我们鉴定了JAK/Stat STAT信号转导途径的受体（称为Marelle或Mom）的受体（Chen等，2002）。 在最近的GLC屏幕中，我们利用了可用的完整果蝇基因组序列。我们首先执行了P元素介导的基因破坏屏幕。通过检查50,000多个突变线，我们分离了2,500个单次插入致命突变体。确定识别850个不同基因或EST的序列> 2300插入的序列（Oh等，2002）。 然后，我们对600个选定的基因进行了GLC分析，其突变在我们的P元素屏幕之前未进行研究。从GLC屏幕中，已经确定了几个新基因“类似跳跃”的基因，它们似乎是JAK/STAT途径的一部分。果蝇依赖性激酶4（CDK4）是这些新基因之一。我们证明了细胞周期蛋白D-CDK4（以及细胞周期蛋白E-CDK2）结合并调节STAT92E蛋白质稳定性（Chen等，2003）。 我们进一步表明，JAK/STAT信号传导和CYCD-CDK4信号传导协同调节了黑色素肿瘤的形成。在眼中，CYCD-CDK4信号传导可防止细胞分化，JAK/STAT信号传导促进细胞增殖。这两个信号之间的合作导致眼睛的“肿瘤般”产物。 我们从果蝇，SOCS44A和SOCS60E克隆了两个SOC基因。我们的结果表明，SOCS60E专门下调JAK/STAT信号传导，SOCS44A主要调节其他信号。 ii。果蝇胚胎背侧闭合期间的上皮细胞片运动 在许多上皮衍生的癌症中，信号最终会导致细胞极性的变化和细胞连接的分解，这是肿瘤转移的初始步骤。果蝇胚胎背闭合（DC）模仿了这些事件，并提供了一个很好的系统来了解这些过程的分子机制。 DC也被用作研究伤口愈合的模型系统。在DC中，前缘处的肌动蛋白动力学之前是与细胞骨架重组有关的主要表皮细胞的极化。 1997年，我们发现了哺乳动物原始癌基因C-Jun基因（DJUN）的果蝇同源物作为DC过程的中心调节剂（Hou等，1997）。 我们最近表征了另一个调节直流过程的基因，即激酶与AP-1（CKA）的连接器。 CKA编码包含多个蛋白质 - 蛋白质相互作用结构域的蛋白质。 CKA与HEP（DJNKK），BSK（DJNK），DJUN和DFO形成复合物。该复合物激活BSK激酶，该激酶磷酸化并激活DJUN和DFO。 CKA代表了一种新的分子，通过组织激酶和转录因子的分子络合物来调节AP-1活性（Chen等，2002）。