LIGHT AND ELECTRON-MICROSCOPIC IN-SITU HYBRIDIZATION - NONRADIOACTIVE LABELING AND DETECTION, DOUBLE HYBRIDIZATION, AND COMBINED HYBRIDIZATION-IMMUNOCYTOCHEMISTRY

We performed light and electron microscopic in situ hybridization, according to the same protocol and without pretreatment of sections, on Lowicryl- and LR Gold-embedded cells. Digoxigenin (DIG)- or biotin-labeled riboprobes were visualized by direct or indirect immunodetection using commercially available gold-antibody conjugates with 0.8-10-nm gold grains. At the ultrastructural level, the main findings were that DIG-labeled probes gave a slightly higher labeling intensity (grains per signal) than biotin. The direct detection method produced a more compact signal, which led to better resolution at medium and high magnifications.