Here, we first delineated the intracellular compartments by nuclear Hoechst33342 and cytoplasmic NEFM staining in motor neurons marked by ISL1+ nuclei, and then measured intracellular FUS levels (Fig. 2b) and the degree of FUS mislocalization within mutant ALS motor neurons in 3D image stacks (Fig. 2c). The gene discussed is ISL1; the disease is amyotrophic lateral sclerosis.