Artificial cell comprising mutant estrogen receptor

An artificial cell comprising:

• (i) a chromosome which comprises a reporter polynucleotide, wherein the reporter polynucleotide comprises an ERE, a TATA sequence and a reporter sequence heterologous to the ERE;
• and
• (ii) a mutant ERα which activates transcription of a polynucleotide downstream from an ERE while exposed to an anti-estrogen which is not antagonistic to an AF1 region of ERα encoded by SEQ ID NO:1 and is antagonistic to an AF2 region of ERα encoded by SEQ ID NO:1, said mutant ERα comprising:
• an amino acid sequence of an ERα comprising one or more substituted amino acids at one or more relative positions selected from 303, 309, 390, 396, 494 and 578, or two or more substituted amino acids at two or more relative positions selected from 303, 309, 390, 396, 415, 494, 531 and 578, wherein the relative positions are based on a homology alignment to an amino acid sequence shown in SEQ ID NO:1.

An isolated mutant ERα having:

• an activity for transactivation of a reporter polynucleotide, the reporter polynucleotide comprising an EKE, a TATA sequence and a reporter sequence heterologous to the ERE, wherein
• in the presence of a partial anti-estrogen and E2 the activity is higher than that of ERα encoded by SEQ ID NO:1 in the presence of the partial anti-estrogen and E2, or
• in the presence of a partial anti-estrogen the activity is higher than that of ERα encoded by SEQ ID NO:1 in the presence of the partial anti-estrogen;
• and
• an amino acid sequence of an ERα comprising one or more substituted amino acids at one or more relative positions selected from 303, 309, 390, 396, 494 and 578, or two or more substituted amino acids at two or more relative positions selected from 303, 309, 390, 396, 415, 494, 531 and 578, wherein the relative positions are based on a homology alignment to an amino acid sequence shown in SEQ ID:1.