Fluorescence imaging of intracellular nucleases-A review.

Nucleases play crucial roles in maintaining genomic integrity. Visualization of intracellular distribution and translocation of nucleases are of great importance for understanding the in-vivo physiological functions of these enzymes and their roles in DNA repair and other cellular signaling pathways. Here we review the recently developed approaches for fluorescence imaging of nucleases in various eukaryotic cells. We mainly focused on the immunofluorescence techniques, the genetically encoded fluorescent probes and the chemically synthesized fluorescent DNA-substrate probes that enabled in-situ visualization of the subcellular localization of nucleases and their interactions with other protein/DNA molecules within cells. The targeted nucleases included important endonucleases, 3' exonucleases and 5' exonucleases that were involved in the DNA damage repair pathways and the intracellular DNA degradation. The advantages and limitations of the available tools were summarized and discussed.