The tetracycline repressor (TetR) is a transcriptional regulator which normally binds tightly to its palindromic tetO operator DNA, blocking gene expression.1 Tet causes the repressor to dissociate from the DNA, allowing transcription to occur. A novel reverse TetR (revTetR) requires tetracycline as a co-repressor to bind tetO and block transcription.2,3 Anhydrotetracycline (hydrochloride) is a powerful effector in both the TetR and revTetR systems, binding the TetR 35-fold more strongly than Tet.4,1 Moreover, anhydrotetracycline poorly binds the 30S ribosomal subunit, compared to Tet,5 so it does not act as a general inhibitor of translation and is a poor antibiotic. Perhaps related to this, the concentration of anhydrotetracycline that inhibits eukaryotic cell growth is more than a 1,000-fold above the dose that alters transcription through TetR.1
1
Gossen, M., and Bujard, H. Anhydrotetracycline, a novel effector for tetracycline controlled gene expression systems in eukaryotic cells. Nucleic Acids Res21(18)4411-4412(1993).
2
Kamionka, A., Bogdanska-Urbaniak, J., Scholz, O., et al. Two mutations in the tetracycline repressor change the inducer anhydrotetracycline to a corepressor. Nucleic Acids Res32(2)842-847(2004).
3
Resch, M., Striegl, H., Henssler, E.M., et al. A protein functional leap: How a single mutation reverses the function of the transcription regulator TetR. Nucleic Acids Res36(13)4390-4401(2008).
4
Degenkolb, J., Takahashi, M., Ellestad, G.A., et al. Structural requirements of tetracycline-Tet repressor interaction: Determination of equilibrium binding constants for tetracycline analogs with the Tet repressor. Antimicrob Agents Chemother35(8)1591-1595(1991).
5
Rasmussen, B., Noller, H.F., Daubresse, G., et al. Molecular basis of tetracycline action: Identification of analogs whose primary target is not the bacterial ribosome. Antimicrob Agents Chemother35(11)2306-2311(1991).
Gossen, M., and Bujard, H. Anhydrotetracycline, a novel effector for tetracycline controlled gene expression systems in eukaryotic cells. Nucleic Acids Res21(18)4411-4412(1993).
Kamionka, A., Bogdanska-Urbaniak, J., Scholz, O., et al. Two mutations in the tetracycline repressor change the inducer anhydrotetracycline to a corepressor. Nucleic Acids Res32(2)842-847(2004).
Resch, M., Striegl, H., Henssler, E.M., et al. A protein functional leap: How a single mutation reverses the function of the transcription regulator TetR. Nucleic Acids Res36(13)4390-4401(2008).
Degenkolb, J., Takahashi, M., Ellestad, G.A., et al. Structural requirements of tetracycline-Tet repressor interaction: Determination of equilibrium binding constants for tetracycline analogs with the Tet repressor. Antimicrob Agents Chemother35(8)1591-1595(1991).
Rasmussen, B., Noller, H.F., Daubresse, G., et al. Molecular basis of tetracycline action: Identification of analogs whose primary target is not the bacterial ribosome. Antimicrob Agents Chemother35(11)2306-2311(1991).