Tagetitoxin inhibits RNA synthesis directed by RNA polymerases from chloroplasts and Escherichia coli

• Published in: The Journal of biological chemistry Vol. 265; no. 1; pp. 493 - 498
• Main Authors: Mathews, D.E. (University of Minnesota, St. Paul, MN), Durbin, R.D
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 05.01.1990
• Subjects: Bacteriophages - enzymology; Biological and medical sciences; BLE; CEREAL GERMS; Chloroplasts - enzymology; Chloroplasts - metabolism; Dicarboxylic Acids - pharmacology; DNA - biosynthesis; DNA-Directed RNA Polymerases - antagonists & inhibitors; ESCHERICHIA; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; GERME DE CEREALE; GERMENES DE CEREALES; INHIBITION; Molecular and cellular biology; Molecular genetics; Organophosphorus Compounds - pharmacology; PHYTOTOXINS; PISUM; PLASTE; PLASTIDIOS; PLASTIDS; Protein Biosynthesis; PSEUDOMONAS; Pseudomonas - metabolism; PSEUDOMONAS SYRINGAE; RNA - biosynthesis; TOXINAS; TOXINE; TOXINS; Transcription, Genetic; Transcription. Transcription factor. Splicing. Rna processing; TRANSFERASAS; TRANSFERASE; TRANSFERASES; TRIGO; WHEATS; Pseudomonadales; In vitro transcription; Radiolabelling; Enzyme; Escherichia coli; RNA polymerase; Autoradiography; Toxin; Pseudomonas syringae; RNA synthesis; Reaction inhibition; RNA polymerase 2; Bacteria; Pseudomonadaceae; Escherichieae; Nucleic acid; Chloroplast; Enterobacteriaceae
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(19)40258-5

Tagetitoxin, a chlorosis-inducing phytotoxin produced by Pseudomonas syringae pv. tagetis, inhibits RNA synthesis directed by chloroplast RNA polymerase. In isolated chloroplasts, tagetitoxin quickly and specifically reduced the incorporation of [3H]uridine into RNA. When it was added to transcriptionally active chloroplast protein extracts, the toxin directly inhibited incorporation of [32P]UTP into RNA. In addition, tagetitoxin inhibited in vitro RNA synthesis directed by the RNA polymerase from Escherichia coli. In vitro transcription reactions directed by chloroplast RNA polymerase or E. coli RNA polymerase are inhibited at tagetitoxin concentrations less than 1 microM. Nuclear RNA polymerase II purified from wheat germ was only affected at tagetitoxin concentrations greater than 100 microM during in vitro transcription. Tagetitoxin concentrations as high as 1 mM did not affect in vitro transcription reactions directed by RNA polymerase from bacteriophage T7 or SP6.