In situ-Hybridization of wild type Drosophila embryos at different developmental stages for the RNA from a gene called hunchback.

In situ hybridization (ISH) is a type of hybridization that uses a labeled complementary DNA or RNA strand (i. Hybridization is the process discovered by Alexander Rich, of combining complementary single-stranded Nucleic acids into a single Molecule. In Genetics, complementary DNA ( cDNA) is DNA synthesized from a mature MRNA template in a reaction catalyzed by the enzyme Reverse Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units e. , probe) to localize a specific DNA or RNA sequence in a portion or section of tissue (in situ), or, if the tissue is small enough (e. In Molecular biology, a hybridization probe is a fragment of DNA or RNA of variable length (usually 100-1000 bases long which is used to detect in DNA Tissue is a cellular organizational level intermediate between cells and a complete organism In situ (ɪn siːˈtuː is a Latin phrase meaning in the place. g. plant seeds, Drosophila embryos), in the entire tissue (whole mount ISH). Drosophila is a Genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" This is distinct from immunohistochemistry, which localizes proteins in tissue sections. Immunohistochemistry or IHC refers to the process of localizing proteins in cells of a tissue section exploiting the principle of antibodies binding specifically DNA ISH can be used to determine the structure of chromosomes. Genome mapping is the creation of a Genetic map assigning DNA fragments to Chromosomes When a Genome is first investigated this map is nonexistent Fluorescent DNA ISH (FISH) can, for example, be used in medical diagnostics to assess chromosomal integrity. FISH ( Fluorescent In situ hybridization) is a cytogenetic technique that can be used to detect and localize the presence or absence RNA ISH (hybridization histochemistry) is used to measure and localize mRNAs and other transcripts within tissue sections or whole mounts.

Process

For hybridization histochemistry, sample cells and tissues are usually treated to fix the target transcripts in place and to increase access of the probe. As noted above, the probe is either a labeled complementary DNA or, now most commonly, a complementary RNA (riboprobe). In Genetics, complementary DNA ( cDNA) is DNA synthesized from a mature MRNA template in a reaction catalyzed by the enzyme Reverse Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units The probe hybridizes to the target sequence at elevated temperature, and then the excess probe is washed away (after prior hydrolysis using RNase in the case of unhybridized, excess RNA probe). Solution parameters such as temperature, salt and/or detergent concentration can be manipulated to remove any non-identical interactions (i. e. only exact sequence matches will remain bound). Then, the probe that was labeled with either radio-, fluorescent- or antigen-labeled bases (e. g. , digoxigenin) is localized and quantitated in the tissue using either autoradiography, fluorescence microscopy or immunohistochemistry, respectively. Digoxigenin (DIG is a Steroid found exclusively in the flowers and leaves of the plants Digitalis purpurea and Digitalis lanata An autoradiograph is an image on an X-ray film or nuclear emulsion produced by the pattern of decay emissions (e A fluorescence microscope (colloquially synonymous with epifluorescent microscope) is a light Microscope used to study properties of organic or inorganic substances Immunohistochemistry or IHC refers to the process of localizing proteins in cells of a tissue section exploiting the principle of antibodies binding specifically ISH can also use two or more probes, labeled with radioactivity or the other non-radioactive labels, to simultaneously detect two or more transcripts.

References

1. Jin L, Lloyd RV. In situ hybridization: methods and applications. J Clin Lab Anal. 11(1):2-9, 1997. PMID 9021518
2. Comprehensive and annotated in situ hybridization histochemistry

External links

• MeSH In+Situ+Hybridization
• Whole-Mount In Situ Hybridization of RNA Probes to Plant Tissues
• Preparation of Complex DNA Probe Sets for 3D FISH with up to Six Different Fluorochromes
• Transcript In Situ Hybridization of Whole-Mount Embryos for Phenotype Analysis of RNAi-Treated Drosophila