Fluorescent in situ transcription in cells and tissues.

This method assesses cellular mRNA transcripts in tissue sections and cell cultures using unique short anti-sense primers directed against sequences in particular protein(s). The unlabeled synthetic cDNA oligonucleotide primers are extended complementary to a sense mRNA transcript using reverse transcriptase and labeled through incorporation of a fluorescent-labeled dUTP nucleotide base. The new cDNA will be synthesized upstream from the point of primer hybridization, and has a specific activity of fluorescent labeling dependent upon the length of the template mRNA from the primer location to the 5'-terminus. This procedure provides rapid detection of low abundance mRNA messages that can be related to other cellular protein components, labeled experimentally with alternative fluorochromes.