PURIFICATION AND QUANTITATIVE-ANALYSIS OF NUCLEIC-ACIDS BY ANION-EXCHANGE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A novel and reliable high-performance liquid chromatography (HPLC) method is described for the purification and quantification of double-stranded DNA. The nucleic acids may be obtained by polymerase chain reaction (PCR) or as restriction fragments from enzymatic cleavage, the separated products are devoid of contaminating material like agarose, ethidium bromide or non-specific DNA sequences. Because of the non-destructive nature of this HPLC procedure, the purified DNA is optimally suited for cloning experiments. The DNA separation by HPLC has major advantages when combined with reverse transcription (RT)PCR. This is exemplified by analysis of the TNF-alpha mRNA obtained from endotoxin-elicited rat liver macrophages. If the standard procedure of Northern blotting is compared with the combination of RT-PCR and quantification of the PCR products by HPLC, it is obvious that the dynamic changes of tumor necrosis factor (TNF)-alpha mRNA synthesis are at least as precisely reflected with the RT-PCR/HPLC combination. The latter method is presented as a reliable and powerful tool for quantitative studies on gene expression.