high background slot blots

[Mike Rott]

I have been having problems with high backgrounds on my DNA slot blots.  I
am using a BioRad slot blot apparatus and their Nylon -1 membrane. My
hybridization solution is:
 
5x SSPE
5x Denharts
0.5% SDS
100ug/ml denatured salmon sperm DNA

65 C, prehyb for at least 1 hour, o/n hybridization

probe is a 32Plabelled cDNA to total mRNA primed with oligo dT

high strigency wash to 0.1x SSC/0.1% SDS 65 C 10 min.


any suggestions on what to try differently?

Thanks,

Mike