A procedure for RT-PCR amplification of mRNAs on histological specimens.

Detection in combination with localization of low copy gene expression can be difficult to achieve. The use of reverse transcription PCR on tissue sections with a fluorescent marker provides localization of mRNA expression on a cellular level, and when combined with confocal microscopy and image analysis it also allows for an estimate of the relative intensity of fluorescence. A good example of the application of this method is the localization of nerve growth factor (NGF) mRNA expression in the inner ear. NGF through indirect tests appears to be present in this system, yet NGF mRNA could not be localized with in situ hybridization using radiolabeled riboprobes. Using fluorescent in situ RT-PCR, we can easily detect the presence of NGF mRNA and localize it to specific cell types within the maturing inner ear.