Matthew Sachs msachs at ADMIN.OGI.EDU
Tue Jan 21 13:21:50 EST 1997

>Would you somebody tell me why do I need to put 3-AT in yeast
>two-hybrid selection?  How does exactly 3-AT work?  I am a beginner in
>yeast and I need your help.
>Karen Yoas
>Biological & Biochemical Sciences
>University of Houston
>Houston, TX 77204-5934

3-amino-1,2,4-triazole (3-AT) competitively inhibits imidazole glycerol
phosphate dehydratase, a His biosynthetic enzyme (Hilton et al., 1965;
Klopotowski and Wiater, 1965; Wiater et al., 1971), and therefore can limit
histidine biosynthesis and growth.  For two-hybrid screens that use 3-AT, a
HIS3 reporter is employed - this gene encodes the enzyme activity inhibited
by 3AT.  High expression of this reporter gene, which arises from a
successful two-hybrid interaction, can overcome the growth-inhibitory
effect of 3-AT in the medium.  Therefore, the use of 3-AT and the HIS3
reporter enables positive selection for successful two-hybrid interactions.

Hilton, J. L., Kearney, P. C., and Ames, B. N. (1965). Mode of action of
the herbicide 3-amino-1,2,4-triazole (amitrole):  inhibition of an enzyme
of histidine biosynthesis. Arch. Biochem. Biophys. 112, 544-547.

Klopotowski, T., and Wiater, A. (1965). Synergism of aminotriazole and
phosphate on the inhibition of yeast imidazole glycerol phosphate
dehydratase. Arch. Biochem. Biophys. 112, 562-566.

Wiater, A., Hulanicka, D., and Klopotowski, T. (1971). Structural
requirements for inhibition of yeast imidazoleglycerol phosphate
dehydratase by triazole and anion inhibitors. Acta Biochim. Pol. 18,

Matthew Sachs
Department of Chemistry, Biochemistry and Molecular Biology
Oregon Graduate Institute of Science and Technology
20000 NW Walker Road
P.O. Box 91000
Portland, OR  97291-1000
503 690-1487 Phone
503 690-1464 Fax
msachs at admin.ogi.edu

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