FET protein localization in cultured human cells. (a) Actively proliferating cells stained with antibodies for FET proteins. FUS and TAF15 show both nuclear and cytoplasmic localization while EWS is found solely in nuclei. Scale bars indicate 10 μm. (b) HT-1080 cells stably expressing FET-GFP proteins show nuclear localization of all three proteins and in addition cytoplasmic localization for FUS-GFP and TAF15-GFP. Scale bars indicate 10 μm. (c) Western blots showing FET-GFP proteins of expected sizes and specificity of FET antibodies used. Wells contain the following lysates: FUS-GFP clone 1 (1), EWS-GFP clone 1 (2), TAF15-GFP clone 1 (3), GFP clone 1 (4), HT-1080 (5), FUS-GFP clone 2 (6), EWS-GFP clone 2 (7), TAF15-GFP clone 2 (8), GFP clone 2 (9). No crossreactivity is seen between different FET antibodies. Endogenous FET proteins correspond to the lower bands seen in all lanes and tagged FET proteins to upper bands. GFP adds approximately 27 kDa to the total size of the respective protein. FUS-GFP and EWS-GFP are expressed at slightly augmented levels compared with their endogenous counterparts while TAF15-GFP is expressed at much higher levels than wild type TAF15.