CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500 007, India.
J Biosci. 2020;45.
GAGA associated factor (GAF) is a sequence-specific DNA binding transcription factor that is evolutionarily conserved from flies to humans. Emerging evidence shows a context-dependent function of vertebrate GAF (vGAF, a.k.a. ThPOK) in multiple processes like gene activation, repression, and enhancer-blocking. We hypothesize that context-dependent interaction of vGAF with a diverse set of proteins forms the basis for the multifunctional nature of vGAF. To this end, we deciphered the protein-protein interactome of vGAF and show that vGAF interacts with chromatin remodelers, RNA metabolic machinery, transcriptional activators/ repressors, and components of DNA repair machinery. We further validated the biological significance of our protein-protein interaction data with functional studies and established a novel role of vGAF in DNA repair and cell-survival after UV-induced DNA damage. One of the major risk factors for skin cutaneous melanoma is prolonged exposure of UV and subsequent DNA damage. vGAF is highly expressed in normal skin tissue. Interestingly, our analysis of high-throughput RNA-sequencing data shows that vGAF is heavily downregulated across all major stages of skin cutaneous melanoma suggesting its potential as a diagnostic biomarker. Taken together, our study provides a plausible explanation for the diverse gene regulatory functions of vGAF and unravels its novel role in DNA repair.
GAGA 相关因子（GAF）是一种序列特异性 DNA 结合转录因子，从果蝇到人类在进化上都是保守的。新出现的证据表明脊椎动物 GAF（vGAF，又名 ThPOK）在多种过程中具有上下文相关的功能，如基因激活、抑制和增强子阻断。我们假设 vGAF 与一组多样化的蛋白质的上下文相关相互作用是 vGAF 多功能性质的基础。为此，我们破译了 vGAF 的蛋白质-蛋白质互作组，并表明 vGAF 与染色质重塑因子、RNA 代谢机制、转录激活因子/抑制因子以及 DNA 修复机制的组成部分相互作用。我们进一步通过功能研究验证了我们的蛋白质-蛋白质相互作用数据的生物学意义，并确立了 vGAF 在 UV 诱导的 DNA 损伤后的 DNA 修复和细胞存活中的新作用。皮肤皮肤黑色素瘤的一个主要危险因素是长时间暴露于 UV 并随后发生 DNA 损伤。vGAF 在正常皮肤组织中高度表达。有趣的是，我们对高通量 RNA 测序数据的分析表明，vGAF 在皮肤皮肤黑色素瘤的所有主要阶段都被严重下调，这表明它可能是一种诊断生物标志物。总之，我们的研究为 vGAF 的多种基因调控功能提供了合理的解释，并揭示了其在 DNA 修复中的新作用。
