INSITU HYBRIDIZATION

Although several molecular biology techniques can be used to measure mRNA, only in situ hybridization (or in situ transcription) permit specific localization of DNA or an mRNA species within a tissue section or cell preparation. With appropriate fixation, mRNAs can be preserved and detected in tissue sections by using DNA or RNA probes labeled with radioactive or chemically modified nucleotides. In situ hybridization has been widely used in molecular and developmental biology to understand gene regulation in tissues and to localize the position of cloned genes on chromosomes. With the introduction of non-isotopic labeling techniques and commercial kits, in situ can be useful for detecting viral RNA or DNA or other genes of interest (like cancer-related oncogenes) in tissue specimens. The development of in situ hybridization is to molecular biology as immunofluorescence and immunoperoxidase staining have been to protein biochemistry, enabling localization and temporal relation of specific mRNAs. © 1991.