Image shows a z-series of a mouse ES cell observed using 3D immuno-FISH. The ES cells carried a multi-copy insertion of an alpha-globin BAC. H3K9me3 immunostaining (red) is shown in comparison to vector backbone FISH signal (green) and DAPI staining (blue).
Formaldehyde fixed cells were imaged using an IMT-2 Olympus fluorescence microscope with 60x 1.4 NA objective lens. Z-series were recorded, and the slices processed by iterative constrained deconvolution. Pixel dimensions are 0.067 microns (xy) with z-spacing 0.2 microns. See also: P Sinclair et al. 2010 Dynamic plasticity of large scale chromatin structure revealed by self-assembly of engineered chromosome regions. J Cell Biol 109:761-776.