Mouse brain sections were immunostained with a mouse monoclonal antibody detecting both human
mutant and mouse endogenous FUS proteins. (A) Cells of the cortex and brainstem
in TG mice displayed prominent FUS immunoreactivity in the cytoplasm (white
arrowheads). Large FUS-positive, round inclusions were also frequently observed
in the cytoplasm of these cells (black arrowheads). Purkinje cells of the
cerebellum (black arrows), however, displayed only very slight staining in the
cytoplasm. In WT mice, the cellular localization of FUS is predominantly
nuclear. (B) Immunofluorescent staining for FUS and DAPI counterstaining of cell
nuclei revealed a granular pattern (white arrows) and the presence of
FUS-positive inclusions (white arrowhead) in the cytoplasm of cortical cells.
(C) Double immunofluorescent staining for FUS and the neuronal nuclear marker,
NeuN, demonstrated that cytoplasmic mislocalization of FUS is widespread in
cortical neurons of TG mice. Scale bars: A,B, 25 μm; C, 100
μm.