Fig. 1. Detection of SV2 isoforms in pancreatic endocrine cells. (A) PCR amplification of SV2 cDNAs from rat brain, INS-1E cells and rat islet ß-cells purified by FACS. Control PCR reactions with no reverse transcriptase were performed for each isoform (-). The DNA size markers (bp) are also indicated. (B) Homogenates of rat brain (10 µg), rat islets and INS-1E cells (100 µg each) were separated by SDS-PAGE and subjected to immunoblotting with the monoclonal antibody against SV2 and with rabbit polyclonal antibodies against SV2A, SV2B or SV2C. Positions of molecular size markers are indicated in kDa. (C) Pancreatic endocrine cells were analyzed by confocal microscopy after double immunofluorescence with an antibody against glucagon (a), somatostatin (d) or pancreatic polypeptide (g) (revealed using FITC-coupled antibody) and with the anti-SV2 antibody (b, e and h) (detected using Rhodamine-coupled antibody). The merged images (c, f and i) were obtained after superposition of the green and red channels. Bars, 5 µm.