To test this hypothesis, we measured the association of CaMKIIα mRNA with PABP in the hippocampus of WT and Paip2a−/− mice using a ribonucleoprotein

immunoprecipitation (RIP) assay with PABP antibody. The association of PABP with CaMKIIα mRNAs was increased after contextual training in both groups. However, the Fulvestrant increase was greater in Paip2a−/− mice as compared to WT mice ( Figure 6F). Taken together, our data demonstrate that, while translation of CaMKIIα mRNA is not altered in Paip2a−/− mice under basal conditions, contextual training of Paip2a−/− mice leads to enhanced CaMKIIα mRNA translation. This is consistent with previous studies showing that the CaMKIIα mRNA contains two cytoplasmic polyadenylation elements (CPEs), binds the CPE binding protein, and undergoes NMDA- and experience-dependent elongation of poly(A) tail at synapses ( Huang et al., 2002; Wu et al., 1998). Translational activation by newly formed poly(A) tail depends on PABP binding, which, in turn, is regulated by PAIP2A.

We next examined the enhancement of CaMKIIα mRNA translation in Paip2a−/− mice by using immunostaining. Previous studies reported Baf-A1 molecular weight that tetanic stimulation increases CaMKIIα levels in CA1 pyramidal cell dendrites of acute hippocampal slices as early as 5 min after the stimulation in a protein synthesis-dependent manner ( Gong et al., 2006; Ouyang et al., 1999). Tetanus-induced dendritic translation of CaMKIIα mRNA in CA1 pyramidal cells in acute hippocampal slices from WT and Paip2a−/− mice was examined. A surgical cut was made across the CA1 area perpendicularly to the pyramidal cell layer to separate tetanized and untetanized slice

regions ( Gong et al., 2006). Thirty minutes after tetanic stimulation, slices Thalidomide were fixed and processed for CaMKIIα fluorescent immunostaining, and the ratio of the CaMKIIα fluorescent signal from the dendritic area of the stimulated and the control sides was calculated. 1HFS induced no change in CaMKIIα amounts in WT slices ( Figures 7A and 7D), but in Paip2a−/− slices, 1HFS led to a significant increase in CaMKIIα expression (WT: 3.8% ± 1.9%; Paip2a−/−: 34.5% ± 9.7%, p < 0.01; Figures 7B and 7D). The increase in dendritic expression of CaMKIIα in Paip2a−/− slices was abolished when anisomycin was present during tetanization ( Figures 7C and 7D), demonstrating that increased levels of CaMKIIα protein is due to upregulation of CaMKIIα mRNA translation. These results indicate that, as with L-LTP, the threshold for induction of dendritic CaMKIIα mRNA translation is lowered in Paip2a−/− slices. It is striking that TBS increased CaMKIIα levels to a greater degree in Paip2a−/− slices than in WT slices (WT: 14.5% ± 2.3%; Paip2a−/−: 45.8% ± 15.4%, p < 0.05; Figure 7E), which supports in vivo results that demonstrate increased CaMKIIα mRNA translation following behavioral training.