Chromosome Counting at Meiosis and Mitosis of Mouse Oocytes and Embryos Using Super-Resolution Live-Cell Imaging and...

Live cell imaging techniques are now essential for capturing chromosomal segregation in fertilized eggs. Although better spatiotemporal resolution of fluorescence observations could provide more information, higher phototoxicity may occur. Super-resolution microscopy is generally considered unsuitable for live cell imaging because of the considerable cell damage. Here, we developed a method for counting chromosomes in mouse living oocytes and early embryos using super-resolution microscopy based on disk confocal photon reassignment microscopy (OPRA). In this chapter, we describe the imaging conditions for minimally invasive, high-resolution observation of mouse oocytes and embryos and a method to count chromosomes via CRISPR/dCas-mediated live-cell fluorescence in situ hybridization.