Pratihar Sumon, Suseela Yelisetty Venkata, Govindaraju Thimmaiah
Bioorganic Chemistry Laboratory, New Chemistry Unit and School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, P.O., Bengaluru, Karnataka 560064, India.
ACS Appl Bio Mater. 2020 Oct 19;3(10):6979-6991. doi: 10.1021/acsabm.0c00870. Epub 2020 Sep 19.
The interplay of condensation and decondensation of DNA plays a crucial role in chromosome maintenance and gene expression. The molecular architectonics governing the chromatin condensation-decondensation cycle are worth studying, as DNA performs unique and distinct roles in each state and switches between two states without the loss of structural and functional integrity. This phenomenon has been adapted and implemented in transfection studies. Effective gene delivery into the cells to achieve respectable transfection efficiency has remained a challenge and emphasizes the need for understanding the steps involved in DNA delivery and transfection. Especially, recognizing the factors that effectively regulate DNA decondensation can provide logical solutions to the hurdles affecting the transfection efficiency. We designed a set of small molecule-based threading intercalation ligands as model condensing agents to study various factors influencing the DNA condensation and decondensation process. This study revealed condensation of DNA into nanocondensate by the threading intercalator and endogenous stimuli induced effective decondensation. Further, DNA nanocondensates are tracked using the intrinsic fluorescence in the lower pH of endocytic pathway and were evaluated as nonviral vectors for in cellulo delivery of plasmids. The correlation of decondensation of DNA nanocondensate with endogenous metal ions at their physiological concentrations provided valuable insights and implications for intracellular DNA delivery.
DNA的凝聚与解凝聚之间的相互作用在染色体维持和基因表达中起着至关重要的作用。由于DNA在每种状态下都发挥着独特且不同的作用，并且在两种状态之间切换时不会丧失结构和功能完整性，因此研究控制染色质凝聚-解凝聚循环的分子结构值得深入探究。这种现象已被应用于转染研究中。将基因有效递送至细胞以实现可观的转染效率仍然是一项挑战，这凸显了理解DNA递送和转染所涉及步骤的必要性。特别是，识别有效调节DNA解凝聚的因素可为影响转染效率的障碍提供合理的解决方案。我们设计了一组基于小分子的穿线嵌入配体作为模型凝聚剂，以研究影响DNA凝聚和解凝聚过程的各种因素。这项研究揭示了穿线嵌入剂可使DNA凝聚成纳米凝聚物，并且内源性刺激可诱导有效的解凝聚。此外，利用内吞途径较低pH值下的固有荧光对DNA纳米凝聚物进行追踪，并将其评估为用于细胞内递送质粒的非病毒载体。DNA纳米凝聚物的解凝聚与生理浓度下的内源性金属离子之间的相关性为细胞内DNA递送提供了有价值的见解和启示。
