Physiological role of UHRF-2 in pQ pathogenesis. A,
fluorescence micrograph of Htt-NLS-Q97 IB surrounded by coexpressed
FLAG-tagged UHRF-2 in HeLa cells. IBs are visualized by GFP fluorescence;
UHRF-2 was visualized by anti-FLAG and Alexa 546 secondary antibody. Scale
bar = 10 μm. Arrows indicate IB; arrowheads indicate
neighboring cell nuclei expressing UHRF-2 alone. B, Htt-NLS-Q97 IB
transiently expressed in HeLa cells is surrounded by endogenous UHRF-2.
Scale bar = 10 μm. Arrows indicate IBs. C,
ataxin-1-Q78 IBs transiently formed in HeLa cells colocalize with UHRF-2. IB
was labeled with anti-Myc antibody and Alexa 488 secondary antibody. Scale
bar = 2 μm. Arrows indicate IBs. D, DRPLAQ80 IBs
transiently formed in HeLa cells are positive for UHRF-2. IBs are labeled with
anti-FLAG antibody and Alexa 488 secondary antibody. Scale bar = 2
μm. Arrows indicate IBs. E, Htt inclusion is positive for
UHRF-2 in vivo. Section from a 6-week-old R6/2 mouse was stained with
anti-UHRF-2 antibody. Anti-UHRF-2 antibody stained the IBs. IBs are labeled
with anti-ubiquitin antibody. Scale bar = 10 μm. F, DRPLA
inclusion is positive for UHRF-2 in vivo. Section from a postmortem
DRPLA patient was stained with anti-UHRF-2 antibody. Anti-UHRF-2 antibody
stained the IB labeled with anti-ubiquitin antibody. Scale bar = 10
μm. G, UHRF-2 overexpression rescues pQ toxicity in primary
cultured mouse neurons. Mouse primary cortical neurons were cotransfected with
Htt-Q97 and UHRF-2. After 96 h, coverslips were stained with anti-MAP2
antibody to identify neurons. The shape of the neurons determined by neurite
outgrowth was classified into three grades: healthy, fully neurite-grown cells
were grouped as grade 1 (a representative cell is shown in the right upper
panels); cells with moderately grown neurites were grade 2 (middle
panels); cells with unhealthy appearance were grade 3 (lower
panels). At least 100 cells from four different coverslips were counted
for each transfection. Scale bars = 10 μm. Black bars
indicate ±S.E.; *, p = 0.0020; **, p = 0.0407; ***,
p = 0.0009 versus wt NLS. H, UHRF-2 knockdown
enhances pQ toxicity in primary cultured mouse neurons. Mouse primary cortical
neurons were cotransfected with Htt-Q97 and mUHRF-2 or control short hairpin
RNA plasmid. After 96 h, coverslips were stained with anti-MAP2 antibody to
identify neurons. Evaluation was carried out by the same method as in the
overexpression experiment. At least 100 cells from three different coverslips
were counted for each transfection. Black bars indicate S.E.; *,
p = 0.0049; **, p = 0.0182; ***, p = 0.007
versus NLS RNAi (–).