BIO125, FOA plate media and western blot media

=> For FOA plates, the media is -HIS-TRP-LEU-THR+URA 

-LEU -THR for URA3's LEU2 promoter to be active.  The presence of Leucine and Theorine lead to 10 fold drop of LEU2 expression.

-HIS to keep pMSH2

-TRP to keep pSH44 reporter plasmid

+URA for FOA assay, because we are selecting for mutant URA3.
So the FOA media is HIS-TRP-LEU-THR + URA

However, before the FOA plate, yeast cells should be grown in - URA to ensure intact dinucleotide repeat in pSH44.
So the regular media is -URA-HIS-TRP (-LEU-THR)

See Gammie04CBE

=> For MSH2 expression:

Gammie07,

Three type of pMSH2 was mentioned. pMSH2, pGBD-MSH2, and pGAL-MSH2.

The pMSH2 is under endogenous promoter. So, the media should be -His to keep pMSH2.

The pGBD-MSH2 was designed to have a constitutive expression of MSH2 protein with HA tag. This plasmid seems to be used for two-hybrid.

 The pGAL-MSH2 contains a GAL10 promoter.


References
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC294742/pdf/jbacter00572-0372.pdf