Non-radioisotopic labels for in situ hybridisation histochemistry: a histochemist's view

The early development of in situ hybridisation relied heavily upon the use of radioisotopes and autoradiography for the visualisation of specifically hybridised gene probes (Buongiorno-Nardelli & Amaldi, 1969; Gall & Pardue, 1969, 1971). Radioisotopic labelling retains an important role, especially where maximum sensitivity is required, but in recent years a group of techniques employing non-radioisotopic labelling technology have been developed. They have been designed to avoid the perceived drawbacks of radiolabels in terms of safety and inconvenience. In this review I hope to provide a flavour of the range of non-isotopic techniques available, to discuss their relative merits and to divine future developments. Some general methodologies are outlined but these must be considered as general guidelines from which optimal protocols must be individually determined (some detailed protocols are provided in later chapters).