Star 440sx

A super resolution optical CW STED microscope (Leica TCS SP 8 3X) was used to obtain the detailed structures of the IRIF. For the Abberior STAR 440SX an excitation laser wavelength of 470 nm and for the Chromeo505 a wavelength of 514 nm were used. The detection ranges were 473 nm to 504 nm and 518 nm to 580 nm respectively, with a depletion laser at 592 nm. Laser power for the excitation laser is in the range of 1 mW and for the STED laser around 70 mW. The STED laser was subdivided in a lateral STED beam (40% of the energy) and an axial STED beam (60%). The system was aligned with regard to temporal and temperature dependent shift as described before13 . Stacks of cell nuclei (3–5 μm thickness) with a slice distance of 160 nm were acquired with a 100x oil objective (Leica HCX PL APO 100x/1.4 Oil) and a pixel size of 40 nm. The raw data images were processed using spectral unmixing and deconvoluted using Huygens professional (Scientific Volume Imaging) as described before13 , resulting in a lateral resolution of 105 nm and an axial resolution of 200 nm.