Figure 2.

Expression patterns of Preso mRNAs and proteins. A–C, Distribution patterns of Preso mRNAs in the brain. Coronal (A), sagittal (B), and horizontal (C) sections of adult mouse brain (6 weeks) were hybridized with a Preso riboprobe. Ctx, Cortex; Hc, hippocampus; MHb, medial habenular nucleus; St, striatum; Ob, olfactory bulb; Cb, cerebellum. Scale bar, 6 mm. D, Three different Preso antibodies (1495, 1496, and 1488) differentially recognize two Preso bands (upper and lower, indicated by filled and open arrowheads, respectively). Tx, Preso proteins expressed in transfected HEK293T cells. P2, Crude synaptosomal fraction from adult rat brain. E, Brain-specific expression of Preso proteins, revealed by immunoblot analysis of adult rat tissue homogenates. Sk, Skeletal. F, Widespread distribution of Preso proteins in adult rat brain regions. R, Other regions of the brain. PSD-95 and β-tubulin were used as controls. G, Gradual increase in Preso expression during postnatal rat brain development. E, Embryonic day; P, postnatal day; Ad, adult (6 weeks). H, Distribution of Preso in subcellular fractions of rat brain. H, Homogenates; S2, supernatant after P2 precipitation; S3, cytosol; P3, light membranes; LP1, synaptosomal membranes; LS2, synaptosomal cytosol; LP2, synaptic vesicle-enriched fraction. Synaptophysin (SynPhy) was used as control. I, Enrichment of Preso in PSD fractions. Postsynaptic density fractions extracted with Triton X-100 once (PSD I), twice (PSD II), and Triton X-100 and a strong detergent Sarcosyl (PSD III) were immunoblotted with Preso and PSD-95 antibodies. Note that the upper, but not the lower, Preso band is selectively enriched.