基因组不稳定性在肿瘤发生发展过程中起着十分关键的作用。剪接因子突变造成基因组不稳定性并与肿瘤的发生相关，但其分子机制并不完全清楚。我们前期在模式动物果蝇中利用遗传筛选发现一个保守的剪接因子，dNKAP，是潜在的肿瘤抑制基因。dNKAP失活造成果蝇上皮组织过度生长，并与癌基因Rasv12有协同致癌效应。进一步的实验发现dNKAP失活导致R-loop的积累、DNA损伤和基因组不稳定性。dNKAP失活诱导不同细胞产生不同的效应，包括细胞过度增殖、细胞周期阻滞和细胞凋亡。dNKAP失活也引起JNK和JAK/STAT等多个信号通路的激活。本申请项目中，我们将利用果蝇遗传学、细胞生物学、激光共聚焦显微镜、RNA高通量测序、DRIP-Seq、结合生物信息学分析，深入研究dNKAP调控R-loop水平和基因组稳定性的分子机制以及dNKAP失活导致果蝇上皮肿瘤发生的机理。

Genomic instability play crucial roles during tumor initiation and progression. Splicing factor mutations can trigger genomic instability and are associated with tumor initiation. However, the underlying molecular mechanisms are not completely understood. Our preliminary data show that Drosophila dNKAP, one conserved splicing factor, is a potential tumor suppressor. Knockdown of dNKAP leads to tissue overgrowth and exhibits a synergistic effect with oncogenic Rasv12 in promoting tumorigenesis. Moreover, dNKAP depletion results in R-loop accumulation, DNA damage and genomic instability. Knockdown of dNKAP causes cell overproliferation, cell cycle arrest and apoptosis in different cell populations. Multiple signaling pathways, including JNK and JAK/STAT, are activated upon dNKAP knockdown. In this proposal, we aim to use a combination of several methodologies, including fly genetics, cell biology, confocal microscopy, RNA-Seq, DRIP-Seq and bioinformatics, to investigate the roles of dNKAP in regulating R-loop levels and genomic stability and the underlying mechanisms of Drosophila epithelial tumorigenesis induced by dNKAP knockdown.