Problems with yeast two-hybrid system

[Brian M. Cooke]

I am having difficulties with transforming the plasmids pGAD424, pGAD424/fos, 
pGBT9 and pGBT9/jun into S.cerevisiae YGH1.  I have tried the following 
methods all using LiAc: 
Schiestl,RH et al. (1993) Introducing DNA into Yeast by Transformation
Methods:A Companion to Methods in Enzymology  5, 79-85,
Randolph Elble (1992) A Simple and Efficient Procedure for Transforming Yeasts
BioTechniques 13(1), 18-20 and the method described in the Clontech manual 
for the two-hybrid system.  I have been unsuccessful at each attempt and would 
value any advice from more experienced yeast transformers.

Thanks,

Dirk Truman