Cell systems having specific interaction of peptide binding pairs

A yeast cell comprising:

• a) a nucleotide sequence encoding a first heterologous fusion protein comprising a first peptide of a known peptide binding pair, or a segment thereof, wherein the peptide binging pair comprises a ligand and a receptor for the ligand, joined to a transcriptional activation protein DNA binding domain;
• b) a nucleotide sequence encoding a second heterologous fusion protein comprising a second peptide of the known peptide binding pair, or a segment thereof, joined to a transcriptional activation protein transcriptional activation domain;
• wherein binding of the first peptide or segment thereof and the second peptide or segment thereof reconstitutes a transcriptional activation protein, and
• c) a reporter gene activated under positive transcriptional control of the reconstituted transcriptional activation protein, wherein expression of the reporter gene prevents exhibition of a selected phenotype.

A yeast cell comprising:

• a) a nucleotide sequence encoding a first heterologous fusion protein comprising a first peptide of a peptide binding pair, or a segment thereof, joined to a transcriptional activation protein DNA binding domain;
• b) a nucleotide sequence encoding a second heterologous fusion protein comprising a second peptide of the peptide binding pair, or a segment thereof, joined to a transcriptional activation protein transcriptional activation domain;
• wherein the nucleotide sequence encoding either the first or second heterologous fusion protein is present in an effective copy number of at least 5 copies per yeast cell and the nucleotide sequence encoding the other heterologous fusion protein is present at a copy number of 1 or 2 per yeast cell;
• and
• wherein binding of the first peptide or segment thereof and the second peptide or segment thereof reconstitutes a transcriptional activation protein;
• and
• c) a reporter gene activated under positive transcriptional control of the reconstituted transcriptional activation protein, wherein expression of the reporter gene prevents exhibition of a selected phenotype.

A yeast cell comprising:

• a) a nucleotide sequence encoding a first heterologous fusion protein comprising a first peptide of a peptide binding pair, or a segment thereof, wherein the peptide binding pair comprises a ligand and a receptor for the ligand, joined to a transcriptional activation protein DNA binding domain;
• b) a nucleotide sequence encoding a second heterologous fusion protein comprising a second peptide of the binding pair, or a segment thereof, joined to a transcriptional activation protein transcriptional activation domain;
• wherein binding of the first peptide or segment thereof and the second peptide or segment thereof reconstitutes a transcriptional activation protein;
• and
• c) a reporter gene activated under positive transcriptional control of the reconstituted transcriptional activation protein, wherein when the reporter gene is expressed the yeast cell does not grow on a selective medium.

A yeast cell comprising:

• a) a nucleotide sequence encoding a first heterologous fusion protein comprising a first peptide of a peptide binding pair, or a segment thereof, joined to a transcriptional activation protein DNA binding domain;
• b) a nucleotide sequence encoding a second heterologous fusion protein comprising a second peptide of the binding pair, or a segment thereof, joined to a transcriptional activation protein transcriptional activation domain;
• wherein the nucleotide sequence encoding either the first or second heterologous fusion protein is present in an effective copy number of at least 5 copies per yeast cell and the nucleotide sequence encoding the other heterologous fusion protein is present at a copy number of 1 or 2 per yeast cell;
• and
• wherein binding of the first peptide or segment thereof and the second peptide or segment thereof reconstitutes a transcriptional activation protein;
• and
• c) a reporter gene activated under positive transcriptional control of the reconstituted transcriptional activation protein, wherein when the reporter gene is expressed the yeast cell does not grow on a selective medium.

A yeast cell comprising:

• a) a nucleotide sequence encoding a first heterologous fusion protein comprising a first peptide of a known peptide binding pair that bind through extracellular interaction in their natural environment, or a segment thereof, joined to a transcriptional activation protein DNA binding domain;
• b) a nucleotide sequence encoding a second heterologous fusion protein comprising a second peptide of the known peptide binding pair, or a segment thereof, joined to a transcriptional activation protein transcriptional activation domain;
• wherein binding of the first peptide or segment thereof and the second peptide or segment thereof reconstitutes a transcriptional activation protein;
• and
• c) a reporter gene activated under positive transcriptional control of the reconstituted transcriptional activation protein, wherein expression of the reporter gene prevents exhibition of a selected phenotype.

A yeast cell comprising:

• a) a nucleotide sequence encoding a first hetermlogous fusion protein comprising a first peptide of a peptide binding pair that bind through extracellular interaction in their natural environment, or a segment thereof, joined to a transcriptional activation protein DNA binding domain;
• b) a nucleotide sequence encoding a second heterologous fusion protein comprising a second peptide of the binding pair, or a segment thereof, joined to a transcriptional activation protein transcriptional activation domain;
• wherein binding of the first peptide or segment thereof and the second peptide or segment thereof reconstitutes a transcriptional activation protein;
• and
• c) a reporter gene activated under positive transcriptional control of the reconstituted transcriptional activation protein, wherein when the reporter gene is expressed the yeast cell does not grow on a selective medium.