Does RNA - PCR ??

Richard R. Hardy hardy at
Mon Jul 17 09:05:45 EST 1995

In article <DBusA7.Lv5 at>, BABAKER at wrote:

>Does RNA PCR??
>I am doing RT-PCR and get positive results even when just PCRing RNA
>using cDNA primers and Taq DNA Polymerase, with no cDNA or genomic DNA 
>anywhere close by!!
>Is it possible that the gene sequence of the mRNA which would only
>contain 1 or 2 U's instead of the T's in the primers sequence would be
>amplifiable by the cDNA primers? As annealing would probably jump the
>U's in the mRNA for that gene and then continue in the PCR to give 
>the correct sized band?
>I dont think that DNA is contaminating my RNA prep as I use the
>Acid-Guanidinium thiocyanate method of isolation, which should 
>erradicate the DNA.
We have no problem amplifying trace DNA contamination from this type of
"RNA" prep - treat your samples with good-quality DNAase.  Or design
primers that span exons so that the DNA and RNA are different sizes... 
Good luck!

Richard R. Hardy
Member, Institute for Cancer Research
Fox Chase Cancer Center, Philadelphia, PA
(215) 728-2463 - voice
(215) 728-2412 - FAX

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