Bertoncini Anna, Pagano Paola, Macovei Anca
Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Via Ferrata 9, 27100 Pavia, Italy.
Genes (Basel). 2025 Jan 19;16(1):103. doi: 10.3390/genes16010103.
DNA damage response (DDR) is a highly conserved and complex signal transduction network required for preserving genome integrity. DNA repair pathways downstream of DDR include the tyrosyl-DNA phosphodiesterase1 (TDP1) enzyme that hydrolyses the phosphodiester bond between the tyrosine residue of topoisomerase I (TopI) and 3'-phosphate end of DNA. A small TDP1 subfamily, composed of TDP1α and TDP1β, is present in plants. The aim of this work was to investigate the role of the two genes in the DDR context. A series of DDR single and double mutants defective in the , , , , and genes, treated with the genotoxic agents camptothecin (CPT, inhibitor of TopI) and NSC120686 (NSC, inhibitor of TDP1), were used. These compounds were specifically used due to their known impact on the TDP1 function. The effect of the treatments was assessed via phenotypic analyses that included germination percentage, speed, and seedling growth. Subsequently, the expression of the and genes was monitored through qRT-PCR. Overall, the gathered data indicate that the mutant was highly sensitive to NSC120686, both phenotypically and concerning the gene expression profiles. Alternatively, the upregulation of in , , and supports its implication in the replication stress response. The current study demonstrates that genotoxic stress induced by CPT and NSC has a genotype-dependent effect reflected by a differential expression of genes and early phenotypic development.
DNA损伤反应（DDR）是一个高度保守且复杂的信号转导网络，对于维持基因组完整性至关重要。DDR下游的DNA修复途径包括酪氨酰-DNA磷酸二酯酶1（TDP1），该酶可水解拓扑异构酶I（TopI）酪氨酸残基与DNA 3'-磷酸末端之间的磷酸二酯键。植物中存在一个由TDP1α和TDP1β组成的小TDP1亚家族。这项工作的目的是研究这两个基因在DDR背景下的作用。使用了一系列在相关基因中存在缺陷的DDR单突变体和双突变体，并用基因毒性剂喜树碱（CPT，TopI抑制剂）和NSC120686（NSC，TDP1抑制剂）进行处理。由于这些化合物对TDP1功能的已知影响，所以专门使用它们。通过包括发芽率、发芽速度和幼苗生长在内的表型分析来评估处理效果。随后，通过qRT-PCR监测相关基因的表达。总体而言，收集到的数据表明，该突变体在表型和基因表达谱方面对NSC120686高度敏感。另外，在相关突变体中该基因的上调支持其参与复制应激反应。当前研究表明，CPT和NSC诱导的基因毒性应激具有基因型依赖性效应，这通过相关基因的差异表达和早期表型发育得以体现。
