Transcriptomic analyses of the substantia nigra in adult Hipk2−/− mouse brain. A, DAVID GO analyses showed the 12 groups of the upregulated and downregulated genes in the substantia nigra of 2-month-old Hipk2−/− mice. B, C, Grin2a and Grin2c mRNA levels were upregulated in the substantia nigra and cerebral cortex of 2-month-old Hipk2−/− mice, whereas the Grin2b mRNA expression was similar between Hipk2+/+ and Hipk2−/− mice. D, E, Grin2a mRNA was elevated in the substantia nigra of Hipk2−/− from postnatal day 0 (P0) until 2 months old. However, in the cerebral cortex, Grin2a mRNA started to increase from P20 to adulthood. F, G, Grin2a and Grin2c mRNA levels were also robustly increased in Hipk2−/− MEFs, and blocking of HIPK2 kinase activity by its specific inhibitors enhanced Grin2a and Grin2c expression in MEF cells. Data are mean ± SEM from at least three independent experiments. *p < 0.05 (ANOVA). **p < 0.01 (ANOVA). Not significant: p > 0.05.