A Riboprobe, abbreviation of RNA probe, is a segment of labelled RNA that can be used to detect a target mRNA or DNA during in situ hybridization. RNA probes can be produced by in vitro transcription of cloned DNA inserted in a suitable plasmid downstream of a viral promoter. Some bacterial viruses code for their own RNA polymerases, which are highly specific for the viral promoters. Using these enzymes, labeled NTPs, and inserts inserted in both forward and reverse orientations, both sense and antisense riboprobes can be generated from a cloned gene.
Applications
There are two kinds of probes beused during in situ hybridization: Riboprobe and DNA oligonucleotides probes. Riboprobes are essential in study of embryo development in which DNA probes are insufficient. With labelled (fluoresce-dyed, for instance) antisense RNA probes hybridized with developing embryo's mRNA, tracking the expression of genes in different stages of development is possible. RNA probes can be used in detecting either whole embryo's development or just on tissue sections of interest. Capable of binding to transcripted mRNA makes RNA probes important in researches on model organisms: Drosophila, zebrafish, chick, Xenopus and mouse. RNA probes can also be utilized in immunohistochemistry to identify tissue infection in embryos. Viral mRNA can be targeted by its antisense RNA probes, while infected tissues don't have complementary mRNA that can hybiridize with probes; the unique mRNA sequence of each organism makes the detection of expression of certain gene highly effective and accurate.