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Digoxigenin DIG Southern Blots



Digoxigenin DIG Southern Blots

Does anyone out there have experience with using Boehringer-Mannheim's digoxigenin-labeled (DIG-labeled) oligonucleotide probes to detect target genomic DNA on their Southern blots. I am getting good transfer of the genomic DNA to a nylon membrane. I'm having some
problems getting enough of my probe DIG-labeled however. When I do the hybridization, I don't see any bands at all. The DIG-labeled molecular
weight marker ladder shows up fine on my blots however. Any suggestions
will be highly appreciated.


Bob Hummel
Newsgroup archive



First:
Check the efficiency and specific activity of your oligoprobe. Compare
a dot-blotted serial dilution with a standard from Boehringer.


Second:
Transfer a serial dilution of a plasmid containing the target sequence
from gel to a membran and prove the sensitivity of your
hybridization/detection-system. IMHO the sensitivity of your system is
much to low to detect a single copy gene in genomic DNA.


I would switch from oligo probe to a >300bp random primed cDNA probe,
hybridization and washing is easier to handle with a longer probe. In
my experience the sensitivity of your assay will be 10 to 100x
increased.


Hope this helps.

U. Maier
Newsgroup archive


Last update 07-Jul-2001, Rating Good of 7 votes.


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