Z-series image of mouse ES cells carrying an alpha-globin BAC transgene array (clone 7d) transduced with a lentivirus containing an expression cassette for EGFP-LacI. EGFP-LacI binding (green) to the 256mer lac operator repeat contained within the BAC identifies the location of the BAC transgene array relative to the nuclear periphery, highlighted by anti-nuclear pore immunostaining (red), and nuclear interior, revealed by DAPI staining (blue). In contrast to the peripheral localization of beta-globin BAC transgene arrays, the alpha-globin BAC transgene arrays do not show the same bias towards the periphery.
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. 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.