Time lapses of strains containing the 10-kb lacO/LacI-GFP array or containing the dicentric plasmid were performed at room temperature (25°C) using an Eclipse Ti wide-field inverted microscope (Nikon) with a 100× Apo TIRF 1.49 NA objective (Nikon) and Clara charge-coupled device camera (Andor) using Nikon NIS Elements imaging software (Nikon). Time lapses of strains containing the 10-kb lacO/LacI-GFP array were 10 min in duration with 30 s intervals. At each interval a seven-step Z-stack of 300-nm step size was acquired in the GFP, RFP, and Trans channels. Time lapses of strains containing the dicentric plasmid were the same as above but with a duration of 20 min.
Population images of the dicentric plasmid strains and of strains containing the 1.2-kb lacO/LacI-GFP array were imaged at room temperature (25°C) using an Eclipse E600FN microscope (Nikon) with a 100× Plan Apo TIRF 1.45 NA objective (Nikon) and ImagEM EM-CCD digital camera (Hamamatsu) with a custom Lumencor LED illumination system (Lumencor) using MetaMorph 7.7 imaging software (Molecular Devices). Each acquisition was a seven-step Z-stack with a 300-nm step size in the GFP, RFP, and Trans channels.
Population images of the dicentric plasmid strains and of strains containing the 1.2-kb lacO/LacI-GFP array were imaged at room temperature (25°C) using an Eclipse E600FN microscope (Nikon) with a 100× Plan Apo TIRF 1.45 NA objective (Nikon) and ImagEM EM-CCD digital camera (Hamamatsu) with a custom Lumencor LED illumination system (Lumencor) using MetaMorph 7.7 imaging software (Molecular Devices). Each acquisition was a seven-step Z-stack with a 300-nm step size in the GFP, RFP, and Trans channels.