Quantitation of gene expression by means of HPLC analysis of RT-PCR products

A method for the quantitative analysis of specific mRNA species by reverse transcription-polymerase chain reaction (RT-PCR) and subsequent detection of products by means of ion-pair reversed-phase high-performance liquid chromatography (IP-RP-HPLC) on alkylated micropellicular polystyrene-divinylbenzene particles has been developed. For RT-PCR, we used the EZrTth RNA PCR kit (Perkin Elmer). This method allows reverse transcription and amplification of specific target mRNA in a single reaction tube. RT-PCR products were analyzed qualitatively and quantitatively by means of IP-RP-HPLC and UV detection at 254 nm. The enzymatic amplification combined with chromatographic separation and UV detection permitted high precision land intra assay CV < 10%), with good practicability (two pipetting steps only). A total RNA preparation of a tissue that highly expressed the sequence of interest and that was stored in multiple aliquots, was diluted to give a standard curve. This external standard curve was used to define when samples have to be diluted, i.e., when the signal is in the plateau phase of amplification. The validity of the method is demonstrated with the example of human retinoic acid receptor mRNA. (C) 1999 Elsevier Science B.V. All rights reserved.