Two-hybrid screen, yeast southern?

[jplin at husc3.harvard.edu]

Hi,

     I've recently done a two-hybrid screen and have 400+ possible
interacting cDNAs.  There is one protein which I already know
interacts with my bait (and is presumably represented in my
series of positives).  One obvious way of eliminating these
clones would be to do hybridization to yeast plasmid DNA
electroporated into bacteria using probes derived from the
known sequence.  
     What I was wondering is whether I can do a Southern (dot blot)
directly on the yeast.  Has anyone tried this?  Copy number could
be a factor, I suppose... 
     Thanks in advance!

Jeff