HIS3

The HIS3 gene, found in the Saccharomyces cerevisiae yeast, encodes a protein called Imidazoleglycerol-phosphate dehydratase which catalyses the sixth step in histidine biosynthesis.^[1] It is analogous to hisB in Escherichia coli.

Exploits

Mutations in Escherichia coli's analogous gene, hisB allows researchers to select only those individuals expressing the HIS3 gene included on a plasmid. The HIS3 gene is coupled to a certain promoter which can only be activated by successful binding of the relevant transcription factors. This is used in certain methods of bacterial two-hybrid screening to allow the survival of E. coli in which a desired protein-DNA or protein-protein interaction is taking place (Joung et al., 2000)

References

• Joung, J. K., E. I. Ramm and C. O. Pabo (2000). "A bacterial two-hybrid selection system for studying protein-DNA and protein-protein interactions." Proc Natl Acad Sci U S A 97(13): 7382-7.