[bionet.molbio.methds-reagnts] pcr primer dimer help

UOG00113@VM.UOGUELPH.CA (craig) (07/28/90)

Hi I'm doing a PCR reaction with an 18 and a 17mer which is giving me problems-
primer dimer!  I've tried the standard remedies such as changing the annealing
temperatures, magnesium concentration, oligomer concentration, template concent
ration, etc. I've even used Stratagene's PCR enhancer (doesn't work).  I'm usin
g BRL Taq polymerase, 25 cycles of 94 C, 55 C, 72 C, with some slight modificat
ions, 10-100ng polyA RNA, 10-200ng oligomers, 0.5-2.5mM MgCl2, standard PCR con
ditions.  The funny thing is that when I use a purified cDNA insert (i.e. omit
the reverse transcription step with polyA RNA)I have solved the problem by alte
ring my oligo concentrations. No such luck when using message. Any and all sugg
estions are welcome.
Craig Berezowsky, Dept.Molecular Biology, University of Guelph,Ontario,Canada
uog00113@VM.UoGuelph.CA