In situ hybridization of odor-evoked activity dependent genes in the OE. A. The expression of genes that are regulated by activity-dependent processes were analyzed in adult WT and β3GnT2−/− OEs. Calretinin, which is expressed in immature neurons and is greatly enriched in CNGA2−/− mice is unchanged in expression in β3GnT2−/− OEs. The Leucine Rich Repeat Containing (Lccr3b), S100A5, and kirrel2 genes, which are all expressed in mature neurons in WT OEs and down-regulated in CNGA2−/− mice, are also unchanged in levels of mRNA expression. Note that increased cell death in β3GnT2−/− OEs results in a thinner layer of mature neurons . Scale bar = 50 μM in all panels. B. Real-time quantitative PCR analysis of activity-dependent gene expression in microdissected adult wild type and β3GnT2−/− OE samples. Relative levels of Lrrc3b, S100A5 and kirrel2 mRNA in null mice decreases in parallel with the mature neuron marker OMP. Immature neurons expressing GAP-43 correspondingly increase in proportion in the null OE. Consistent with this, calretinin expression in the basal OE is preserved in null mice. Thus, the expression of activity-dependent genes fluctuates only in accordance with the dynamics of the cell population they are expressed in, suggesting that odor-evoked activity is not as severely compromised in β3GnT2−/− mice relative to CNGA2 mutants. Error bars are the mean +/− SEM (n = 3 for GAP-43; n = 6 for all others).