Renin gene expression in various tissues determined by single-step polymerase chain reaction.

1. Renin mRNA is present in the kidney and, in lower concentrations, in many extrarenal tissues and serves as an index of renin gene activity, as well as potential renin or prorenin synthesis in cell populations within those tissues. Unfortunately the quantity can be very low. 2. A new, highly sensitive technique is described for detection of renin mRNA that involves the enzyme Taq polymerase for both reverse transcription of renin mRNA into renin cDNA and for amplification of the 769-1099 nucleotide segment by the polymerase chain reaction (PCR), all of which involves a single reaction mixture. 3. In this way renin mRNA was detected in kidney and several extrarenal tissues as a PCR product of approximately 330 base pairs on agarose gels by ethidium-bromide staining or hybridization probing. The region of renin mRNA chosen for amplification spanned several intron sites in the coding sequence so that the presence of amplicants derived from genomic DNA could be readily discriminated, as a band of approximately 1.5 kilobases. 4. Thus single-step PCR offers a powerful new approach to detection of renin mRNA.