Synthesis of digoxigenin-labeled cDNA as a test for mRNA integrity.

The nucleotide analogue digoxigenin-11-dUTP is widely used as a nonradioactive marker in a broad range of techniques including dot blots, Southern and Northern blots, colony and plaque screenings and in situ hybridizations. In this report, we describe the incorporation of this molecule into a cDNA synthesized by reverse transcriptase as a novel application for digoxigenin. This reaction can be performed as a useful control to check the integrity of a bulk mRNA preparation in the construction of a cDNA library, since the ability of mRNA to direct the synthesis of long molecules of first-strand cDNA is a sign of its integrity.