Translation of satellite tobacco necrosis virus RNA modified by (not equal to)-r-7,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene is inhibited in a wheat germ cell-free system
It has been shown that (not equal to)-r-7-,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) modification of rabbit globin mRNA results in inhibition of translational initiation. In order to explore the possibility that modification of the 5' cap structure was responsible for this inhibition, the naturally non-capped mRNA from satellite tobacco necrosis virus (STNV) was reacted with BPDE and translated in a wheat germ cell-free system. The extent of modification was 1.3 and 2.9 BPDE residues/molecule. High performance liquid chromatography of the modified nucleosides from enzymatically hydrolyzed STNV RNA revealed that greater than 90% of the nucleoside adducts were substituted at the exocyclic amino group of guanosine. The translational ability of the lower and higher modified STNV, measured by incorporation of (/sup 14/C)amino acids into acid-precipitable polypeptides is inhibited by 55% and 63%, respectively. Polyacrylamide gel electrophoretic analyses of the translation products indicate that predominantly full-length coat proteins are synthesized but with the carcinogen-modified STNV the amount is reduced. On the other hand, 80S initiation complex formation is not inhibited as measured by binding of the BPDE-modified STNV to ribosomes and followed by glycerol gradient centrifugation. Under these conditions, aurintricarboxylic acid completely inhibits 80S initiation complex formation in the presence of either modified or native STNV. These results suggest that inhibition of in vitro translation of BPDE-modified STNV, in contrast to that of globin mRNA, is not at the level of initiation complex formation but possibly by premature termination of growing polypeptides.
- Research Organization:
- Columbia University College of Physicians and Surgeons, Department of Biochemistry, Cancer Center/Institute of Cancer Research, New York, NY
- OSTI ID:
- 6225837
- Journal Information:
- Carcinogenesis (N.Y.); (United States), Vol. 4:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BENZOPYRENE
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
TRACER TECHNIQUES
MESSENGER-RNA
TRANSCRIPTION
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
ENZYME INHIBITORS
LIQUID COLUMN CHROMATOGRAPHY
VIRUSES
AROMATICS
CHROMATOGRAPHY
CONDENSED AROMATICS
HYDROCARBONS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PARASITES
REACTION KINETICS
RNA
SEPARATION PROCESSES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques