Tagetin™ RNA Polymerase Inhibitor

Tagetin™ RNA Polymerase Inhibitor




500 U @ 20 U/μl





  • RNA polymerase inhibition studies.
  • Transcription studies.

First discovered as a bacterial phytotoxin responsible for inducing chlorosis, Tagetin™ RNA Polymerase Inhibitor is the only compound known to potently and selectively inhibit RNA polymerase III from a variety of eukaryotic organisms including mammalian cells, Saccharomyces cerevisiaeDrosophila melanogasterBombyx mori, and Xenopus laevis oocytes.1 It strongly inhibits Escherichia coli RNA polymerase and plant chloroplast RNA polymerase.2 Plant nuclear RNA polymerases I, II, and III are much less sensitive to Tagetin Inhibitor. Phage-encoded RNA polymerases such as SP6 and T7 are also relatively insensitive.3 With both eukaryotic and prokaryotic RNA polymerases, the degree of inhibition is template-dependent.4 Tagetin Inhibitor complements the activity of α-amanitin, a potent and selective inhibitor of eukaryotic RNA polymerase II. Although the precise mechanism of inhibition is not understood, studies with yeast nuclear extracts indicate that the effect is due to increased pausing of the elongation complex at discrete points on the template.4



  • Only known specific inhibitor of RNA polymerase III from many nonplant eukaryotes.
  • Specific inhibition of chloroplast RNA polymerase of many plants.

Unit Definition: One unit (30 pmol) of Tagetin Inhibitor results in 50% inhibition of 1 unit of E. coli RNA Polymerase Holoenzyme under standard assay conditions using phage T7 DNA as a template.

Storage Buffer: Tagetin RNA Polymerase Inhibitor is provided in water at a concentration of 20 U/µl (600 µM).

Quality Control: Tagetin Inhibitor is functionally tested with EPICENTRE's E. coli RNA Polymerase Holoenzyme and is free of detectable RNase and DNase activities.


  1. Steinberg, T.H. et al. (1990) J. Biol. Chem. 265, 499.
  2. Mathews, D.E. and Durbin, R.D. (1990) J. Biol. Chem. 265, 493.
  3. Lukens, J.H. et al. (1987) Plant Physiol. 84, 808.
  4. Steinberg, T.H. and Burgess, R.R. (1992) J. Biol. Chem. 267, 20204.
Figure 1
Figure 1. Tagetin Inhibitor activity on E. coli RNA Polymerase. Each gel lane shows products of a standard transcription reaction using a bacteriophage template, 1 U of E. coliRNA Polymerase Holoenzyme, and varying amounts of Tagetin Inhibitor. Lane 1, 100 U; Lane 2, 10 U; Lane 3, 1 U; Lane 4, 0.1 U; Lane 5, control without Tagetin Inhibitor. 50% inhibition of transcription is seen at 1 U Tagetin Inhibitor per unit of E.coliRNA Polymerase.


Catalog No. Concentration Size

Tagetin™ RNA Polymerase Inhibitor
T9705H 20 U/µl 500 Units
T9701K 20 U/µl 1,000 Units
T9702K 20 U/µl 2,500 Units