Confocal Imaging.

Fluorescence imaging was performed using a Nikon Eclipse Ti2 epifluorescence microscope equipped with a CSU-W1 spinning disk confocal module and an Andor 4.2 Zyla sCMOS camera. The system was controlled by NIS-Elements AR 5.21.03 64-bit software. Images were taken using the following Nikon objectives: CFI Plan Apo Lambda 4× (0.2 NA), CFI Plan Apo Lambda 10× (0.45 NA), CFI Apo LWD Lambda S 20×WI (0.95 NA), CFI Apo LWD Lambda S 40×WI (1.15 NA), CFI Plan Apo Lambda 60×Oil (1.4 NA). DAPI was excited with a 405 nm laser and imaged with a 450/50 emission filter, Alexa Flour 488 was excited with a 488 nm laser and imaged with a 525/40 emission filter. Alexa Fluor 546 was excited with a 561nm laser and imaged with a 607/36 emission filter. Alexa Fluor 647 was excited with a 640nm laser and imaged with a 685/40 emission filter. During imaging, the gels were placed in glass-bottom customed plates with all excess liquid removed. Poly-L-lysin coating is recommended recycled imaging plates.