Fig. 3.

High-power photomicrographs of immunostaining with the EM48 antibody in the striatum of a 6-month-old (m.o.) wild-type (A) and 2- (B), 4- (C, D,E), and 6- (F) month old knock-in mice (KI). No or weak cytoplasmic staining was observed in the striatum of wild-type (A) and 2-month-old knock-in mice (B). Note the substantial inter-animal variability of huntingtin staining at 4 months of age, ranging from animals with no staining (C), with nuclear microaggregates in isolated cells (D) (arrow), or with numerous cells displaying nuclear microaggregates (E) (arrows). At 6 months of age, striatal cells contained numerous nuclear microaggregates (F) (arrows). Note that only the nucleus of striatal neurons is immunostained. Scale bar (shown inF): 10 μm. High-magnification microphotographinsets in D, E, andF show EM48 immunoreactivity in the nuclei of striatal cells (insets show 3× magnification of large photomicrograph).