Two Hybrid False Positives?

[als152 at psu.edu]

Hello everyone,

We screened a yeast two-hybrid library in an effort to identify
proteins that interact with a our bait protein. We isolated a clone
that was positive on the B-gal assay; however, I am not always able to
reproduce this result.  I've tried filter assays and sometimes I get a
faint blue color, sometimes no color at all or background levels.  I
recently tried a liquid assay however this did no give a positive
result. Data from independent method suggests that there may be a weak
interaction.  Are there any two hybrid assays (CPRG or agarose overlay
for example) that are more sensitive.  Is there any reliable way to
destinguish between a weak interaction and a false positive?  Any
suggestions would be greatly appreciated.

Andrea Skirpan
Penn State
als152 at psu.edu