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Imaging Replicative Domains in Ultrastructurally Preserved Chromatin by Electron Tomography
Published on: May 20, 2022
Chiral Os(II) Polypyridyl Complexes as Enantioselective Nuclear DNA Imaging Agents Especially Suitable for
Rong Huang1,2, Feng-Ping Feng3, Chun-Hua Huang1,2
1State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , P. R. China.
Abstract:
The high-resolution technique transmission electron microscopy (TEM), with OsO4 as the traditional fixative, is an essential tool for cell biology and medicine. Although OsO4 has been extensively used, it is far from perfect because of its high volatility and toxicity. Os(II) polypyridyl complexes like [Os(phen)2(dppz)]2+ (phen = 1,10-phenanthroline; dppz = dipyridophenazine) are not only the well-known molecular DNA "light-switches" but also the potential ideal candidates for TEM studies. Here, we report that the cell-impermeable cationic [Os(phen)2(dppz)]2+ can be preferentially delivered into the live-cell nucleus through ion-pairing with chlorophenolate counter-anions, where it functions as an unparalleled enantioselective nuclear DNA imaging reagent especially suitable for correlative light and electron microscopy (CLEM) studies in both living and fixed cells, which can clearly visualize chromosome aggregation and decondensation during mitosis simultaneously. We propose that the chiral Os(II) polypyridyl complexes can be used as a distinctive group of enantioselective high-resolution CLEM imaging probes for live-cell nuclear DNA studies.
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