A functionally orthogonal estrogen receptor-based transcription switch specifically induced by a nonsteroid synthetic ligand.
It is highly desirable to design ligand-dependent transcription regulation systems based on transactivators unresponsive to endogenous ligands but induced by synthetic small molecules unable to activate endogenous receptors. Using molecular modeling and yeast selection, we identified an estrogen receptor ligand binding domain double mutant (L384M, M421G) with decreased affinity to estradiol and enhanced binding to compounds inactive on estrogen receptors. Nonresponsiveness to estrogen was achieved by additionally adding the G521R substitution while introducing an "antagonistic-type" side chain in the compound, as in 4-hydroxytamoxifen. The triple-substituted ligand binding domain is insensitive to physiological concentrations of estradiol and has nanomolar affinity for the ligand. In this binary system, both receptor and ligand are, therefore, reciprocally specific. The mutated variant in the context of a chimeric transcription factor provides tight, ligand-dependent regulation of reporter gene expression.
Gallinari
Paola
P
Instituto di Ricerche di Biologia Molecolare P. Angeletti, MRL-Rome, Department of Biochemistry, Via Pontina km 30,600, Pomezia 00040, Italy. paola_gallinari@merck.com
Lahm
Armin
A
Koch
Uwe
U
Paolini
Chantal
C
Nardi
Maria Chiara
MC
Roscilli
Giuseppe
G
Kinzel
Olaf
O
Fattori
Daniela
D
Muraglia
Ester
E
Toniatti
Carlo
C
Cortese
Riccardo
R
De Francesco
Raffaele
R
Ciliberto
Gennaro
G
D019943:Amino Acid Substitution; D001665:Binding Sites / Q000235:genetics; D015195:Drug Design; D004958:Estradiol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D017930:Genes, Reporter; D006801:Humans; D007700:Kinetics; D008024:Ligands; D011993:Recombinant Fusion Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D015003:Yeasts / Q000235:genetics
D047628:Estrogen Receptor alpha; D008024:Ligands; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D004958:Estradiol