Fig 1.

A subset of miRNAs are enriched at nucleus accumbens synapses. (a) miRNAs identified by microarray screening to be consistent between two or more arrays (n = 3; P < 0.01). Total RNA, including small RNA species, was extracted from synaptoneurosomes in three independent preparations and compared to total RNA prepared from whole tissue of the nucleus accumbens via competitive hybridization to microarrays (n = 3). miRNAs that are both enriched and depleted from synaptoneurosomes prepared from the nucleus accumbens region of P15 rats are shown. (b) Differential abundance of miRNAs in synaptoneurosomes. In three separate microarray hybridizations, we identified ∼38 miRNAs that were consistently detected (P < 0.01). Refer to Table 1 for those miRNAs with ≥2-fold enrichment or depletion (P < 0.01) in the synaptoneurosomes. (c) Northern blot validation of miR-181a abundance in synaptoneurosomes (SYN) compared to that in whole tissue (NAcc). Also shown are the expression of miR-124a and U6 snRNA in the SYN and NAcc. Validation of two other miRNAs, miR-139-5p and miR-328, also found to be abundant in the synaptoneurosomes compared to whole tissue. Note the absence of pre-miR-124a from synaptoneurosomes. (d) qRT-PCR validation of miR-181a enrichment in synaptoneurosomes relative to whole tissue in three independent preparations. Data were normalized to the expression of miR-124a, which was equally distributed throughout the cell (Table 1 and Fig. 1c).