The Novel Oncogene Jcf1 in Development and Oncogenesis

描述（由申请人提供）：MoMuLV诱导的大鼠T细胞淋巴瘤中常见整合位点的全基因组筛选，导致鉴定了一种新的癌基因Jcf 1，这是本提案的主题。jcf 1在癌基因中是独特的，因为它促进动物中原发性肿瘤细胞的生长，但在培养中被抑制。由该基因编码的蛋白质长1336个氨基酸，包含jumonji（JmjC）结构域、CXXC/PHD 2锌指结构域、F盒和富含亮氨酸的重复序列（LRR），并且定位于细胞核中。强调JmjC结构域的重要性，这被认为是参与染色质修饰和重塑，是发现146个克隆的三个额外的前病毒整合有靶向基因，也编码含JmjC结构域的蛋白质。使用F-box/LRR结构域作为诱饵的双杂交筛选鉴定了几种参与转录、DNA修复和细胞凋亡调节的相互作用蛋白。此外，稳定或瞬时转染的Jcf 1在细胞系中表达该基因在非常低的水平诱导的内源性基因的表达，从而证实，Jcf 1是一个调节基因的表达。NIH 3 T3细胞的血清饥饿和IL-2依赖性T细胞淋巴瘤细胞系的IL-2饥饿导致Jcf 1表达的急剧下降。再次暴露于血清或IL-2分别诱导Jcf 1迅速，表明Jcf 1可能有一个通过细胞周期的G1期的细胞再进入和进展的作用。此外，在培养的骨髓单核细胞系的分化过程中，Jcf 1的表达下降到不可检测的水平，这表明它可能在髓系细胞分化中起作用。jcf 1是一个高度保守的蛋白质。使用预先存在的Jcf 1Drosphila突变体，产生的P元件插入在前两个内含子的基因，我们证明了DJcf 1是必需的发展过程中。本实验将利用分子生物学、组织培养和遗传学方法来研究Jcf 1在肿瘤发生和发展中的作用。

DESCRIPTION (provided by applicant): A genome-wide screen for loci of common integration in MoMuLV-induced rat T cell lymphomas, led to the identification of a novel oncogene, Jcf1, which is the subject of this proposal. Jcf1is unique among oncogenes, in that it promotes the growth of primary tumor cells in animals but is dispensable in culture. The protein encoded by this gene is 1336 amino acids long, contains a jumonji (JmjC) domain, a CXXC/PHD2 zinc finger domain, an F box and a leucine rich repeat (LRR) and is localized in the nucleus. Underscoring the importance of the JmjC domain, which is thought to be involved in chromatin modification and remodeling, was the finding that three additional provirus integrations among 146 cloned had targeted genes that also encode JmjC domain-containing proteins. A two-hybrid screen using the F-box/LRR domain as the bait identified several interacting proteins that are involved in transcription, DNA repair and the regulation of apoptosis. Moreover, stable or transient transfections of Jcf1in cell lines that express this gene at very low levels induced the expression of the endogenous gene, thus confirming that Jcf1is a regulator gene expression. Serum starvation of NIH 3T3 cells and IL-2 starvation of an IL-2 dependent T cell lymphoma line led to a precipitous drop in Jcf1expression. Reexposure to serum or IL-2 respectively induced Jcf1rapidly, suggesting that Jcf1may have a role in the reentry and progression of cells through the G1 phase of the cell cycle. Moreover, the expression of Jcf1declined to undetectable levels in the course of differentiation of a myelomonocytic cell line in culture suggesting that it may have a role in myeloid cell differentiation. Jcf1is a highly conserved protein. Using preexisting Jcf1Drosphila mutants, generated by P element insertions in the first two introns of the gene, we demonstrated that DJcf1 is required during development. Experiments proposed here will utilize molecular biology, tissue culture and genetic strategies to address the role of Jcf1in development and oncogenesis.