GC rich riboprobes

[David Goldstein]

Dear Al,
I spent considerable time and effort attempting to increase the specific 
hybridization of GC rich probes for use in Northern blots (for riboprobe 
synthesis) as the secondary structure of the transcripts caused 
CONSIDERABLE hybridization to non-specific message.  My advice is to not 
waste a lot of time.  The only method that worked well was RNAse 
protection, which, of course does not give a message  size.  I was able 
to get specific hybridization to my message using poly A+ selection, but 
I still pick up a great deal of extraneous noise on the blots.  I think
that I must have tried every hyb buffer (with up to 80% formamide!) in 
the book.  Incidentally, these messages were approximately 75-85% GC.
Good luck, Rex