endogenous GUS activity

[Charles S. Gasser]

Addition of methanol to 20% during staining or fluorimetric assays
dramatically reduces endogenous GUS-like activity without affecting
introduced E. coli GUS activity.  This is usually not necessary in
Arabidopsis as endogenous activity is low.  We have found it to be
essential in staining Brassica, tomato or tobacco tissues.

Good luck,
Chuck Gasser
csgasser at ucdavis.edu