Figure 7. Suppression of Ub accumulation by additional knockdown of Grp78 in NF-YA/NF-YC knockdown striatal neurons.

(a) AAV-EmGFP-miR-YA/YC was mixed with AAV-EmGFP-miR-NT-2 or -Grp78 at the ratio of 1:1 and was bilaterally injected into striata of wild type B6 mice. Mice were fixed at 3 weeks after injection and processed for cryosectioning in the coronal plane. Sequential sections were used for staining with anti-GFP and Ub antibodies. (b) Enlarged images of boxed regions in (a). Note the suppression of Ub accumulation induced by NF-YA/NF-YC knockdown by additional knockdown Grp78. (c) Number of cells positive for GFP or Ub on the sections were counted and ratios of Ub-positive cells to GFP-positive cells were calculated. More than 1900 of GFP-positive cells were counted for each mouse. Values are means + s.d. of three mice data (*P < 0.05, t-test). (d) Summary of the pathological responses upon NF-Y inactivation in CNS neurons. Our previous data of NF-YA deletion in pyramidal neurons of cortex (Cor) and hippocampus (Hpc) were included². Similar to the pyramidal neurons, MSNs in striatum (Str) and Purkinje cells in cerebellum (Cbl) showed selective downregulation of Grp94 and accumulation of Ub, p62 and membrane proteins including APP and CPE. A slight difference was observed for the Ub accumulation pattern among these neurons. In contrast, the motor neurons in spinal cord (SC) and brain stem (BS) showed downregulation of both Grp78/94 ER chaperones and no accumulation of Ub, p62 or membrane proteins. The Ub accumulation in MSNs induced by NF-Y inactivation was suppressed by additional downregulation of Grp78.