ALS2 and amyotrophic lateral sclerosis: Since their initial characterization, UCHL1-eGFP mice have been extensively used to study UMN degeneration in animal models of ALS, including alsin knockout (KO) and transgenic TDP-43A315T mice [13,29,30,31,50], and therefore are an invaluable tool for uncovering the precise role of UMNs in ALS.