Oligonucleotide probes for in situhybridization

Abstract Oligonucleotide probes are convenient for determining the sites of gene expression using in situ hybridization. Since the probes are synthetic, their use does not require much specialized equipment for molecular biology, the growth of bacteria, or the purification of nucleic acids. Oligonucleotide probes can be designed to form complementary base pairs with a target sequence, that can be RNA or DNA. In this chapter we consider binding of oligo¬ nucleotide probes to RNA targets only. The probe is labelled so that its presence on tissue sections can be detected. Probe is applied to the tissue under conditions that hybridization takes place, and then the sections are washed to remove non-specific binding. After these steps have taken place, the presence of the probe can be detected by autoradiography (for radio¬ labelled probes) or by histochemistry (for non-radiolabelled probes). It is possible to use oligonucleotide probes to measure the level of gene expression in individual cells or in tissues using appropriate image analysis techniques.