RT-PCR and Gene Expression

The application of the polymerase chain reaction technique (PCR) to the study of gene expression, variously referred in the literature to as cDNA-PCR reverse transcription-PCR (RT-PCR) (Chelly et al., 1988; Rappolee et al., 1988a) and sometimes as Patty (PCR aided transcript titration assay, Becker-Andre and Hahlbrock, 1989), represents a dramatic technical innovation. The RT-PCR procedure has proven more sensitive and discriminating than Northern blot analysis, nuclease protection assay, and in situ hybridization. It is rapid and easy to handle, allows simultaneous analysis of several transcripts from total RNA, and can be used for relative or absolute quantification of mRNAs (Chelly et al., 1990a; Rappolee et al., 1989; Becker-Andre and Hahlbrock, 1989; Wang et al., 1989; Singer-Sam et al., 1990; Gilliland et al., 1990). This technique is very powerful in detecting transcripts that have a low copy number because of their short half-life or low rate of transcription and in detecting transcripts from a small number of cells (even from a single cell) or a small amount of tissue (even from a tissue section).