(a) Identification of Drd1 vs. Drd2 enriched gene
expression profiles in striatum. (b) Numbers of Drd2 enriched genes
displaying significant downregulation in Drd2 MSNs following repeated cocaine,
G9a KO, or both. (c) Validation of Drd2 enriched genes
downregulated by G9a KO selectively in Drd2 MSNs. (d) Numbers of
Drd1 enriched genes displaying significant upregulation in Drd2 MSNs following
repeated cocaine, G9a KO, or both. (e) Validation of Drd1 enriched
genes upregulated by G9a KO selectively in Drd2 MSNs. Percentages indicate the
number of Drd2 (b) or Drd1 (d) enriched genes displaying significant regulation
by repeated cocaine, G9a KO, or both, divided by the total number of genes
enriched within a given cell type. (f) Afferent projection terminal
tracing demonstrates that selective loss of G9a in Drd2 neurons leads to
abnormal ‘direct pathway’ projections to midbrain (substantia
nigra) from Drd2 G9a KO MSNs in comparison to wildtype controls. Data are
presented as averages ± SEM.