Department of Pharmacology and Cancer Biology, C318 Levine Science Research Center, Duke University Medical School, Durham, NC 27710, USA.
G3 (Bethesda). 2022 Jul 29;12(8). doi: 10.1093/g3journal/jkac129.
Fanconi anemia genes play key roles in metazoan DNA damage responses, and human FA mutations cause numerous disease phenotypes. In human cells, activating monoubiquitination of the Fanconi anemia protein Fancd2 occurs following diverse DNA damage stimuli. Monoubiquitinated Fancd2 forms nuclear foci to recruit additional repair factors. Fancd2 animal models to date have focused on molecular nulls or whole gene knockdown, leaving the specific in vivo role of monoubiquitination unclear. Using a point mutant in a conserved residue, we recently linked Drosophila Fancd2 monoubiquitination to a mitosis-specific DNA double-strand break response. In this context, we used CRISPR/Cas9 to generate the first animal model of an endogenous mutation in the conserved monoubiquitination site (fancd2K595R). Here, we expand upon our characterization of fancd2K595R. We also introduce and characterize additional Drosophila tools to study fancd2, including new mutant alleles and GFP-tagged rescue transgenes. Using these new reagents, we show the impact of Drosophila Fancd2 on organismal and cell viability, as well as on repair protein localization, in the presence or absence of double-strand breaks. These findings expand our understanding of Fanconi anemia gene function in vivo and provide useful reagents for DNA repair research.
范可尼贫血症基因在后生动物 DNA 损伤反应中发挥关键作用，人类 FA 突变导致许多疾病表型。在人类细胞中，多种 DNA 损伤刺激后，会激活范可尼贫血蛋白 Fancd2 的单泛素化。单泛素化的 Fancd2 形成核焦点，以招募其他修复因子。迄今为止，Fancd2 的动物模型主要集中在分子缺失或整个基因敲低上，单泛素化的具体体内作用尚不清楚。我们最近使用保守残基中的点突变，将果蝇 Fancd2 的单泛素化与有丝分裂特异性 DNA 双链断裂反应联系起来。在这种情况下，我们使用 CRISPR/Cas9 生成了第一个保守单泛素化位点（fancd2K595R）内源性突变的动物模型。在这里，我们扩展了对 fancd2K595R 的描述。我们还引入并描述了其他用于研究 fancd2 的果蝇工具，包括新的突变等位基因和 GFP 标记的拯救转基因。使用这些新的试剂，我们展示了果蝇 Fancd2 对生物体和细胞活力的影响，以及在存在或不存在双链断裂的情况下，对修复蛋白定位的影响。这些发现扩展了我们对体内范可尼贫血症基因功能的理解，并为 DNA 修复研究提供了有用的试剂。
