Development of a test for carcinogens and promoters based on early enzyme changes. Final progress report, March 1, 1983-February 29, 1984

Technical Report · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6219692

Alterations in rat liver (tRNA)methyltransferase activities have been observed after liver damage by several chemicals or by partial hepatectomy. Each of the liver damaging agents tested rapidly caused increases in activities of the enzyme(s) catalyzing methyl group transfer to E. coli tRNAs that have an unmodified guanine at position 26 from the 5' end of the molecule. This group of tRNAs includes E. coli tRNA/sup Nfmet/, tRNA/sup Ala/1, tRNA/sup Leu/1 or /sup Leu/2, and tRNA/sup Ser/3. In each case N/sub 2/-methylguanine and N/sub 2/,N/sub 2/-dimethylguanine represented 90% or more of the products of these in vitro methylations. The product and substrate specificity observed are characteristic of N/sub 2/-guanine methyltransferase II (NMG II). The same liver damaging agents induced little or no change in the activities of enzymes that catalyze methyl group transfer to various other E. coli tRNAs that do not have guanine at position 26. In addition tRNA methyltransferase activities of C57BL/6J, C57L/J, C58/J, AKR/J, and C3H/HeJ inbred mice have been studied. Mice from two strains with high incidence of spontaneous leukemia (AKR/J and C58/J) and the high spontaneous hepatoma strain, C3H/HeJ, exhibited levels of liver NMGII activity that were double those seen in two strains of mice with low incidence of spontaneous cancer (C57BL/6J and C57L/J). The activities of other tRNA base-specific liver tRNA methyltransferases were very similar in all strains studied. 5 figures, 6 tables.

• Research Organization: New York Blood Center, NY (USA)
• DOE Contract Number: AC02-79EV10267
• OSTI ID: 6219692
• Report Number(s): DOE/EV/10267-T2; ON: DE84014903
• Country of Publication: United States
• Language: English

Related Subjects

560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
BODY
DATA
DIGESTIVE SYSTEM
ENZYME ACTIVITY
ENZYMES
EXPERIMENTAL DATA
GLANDS
INFORMATION
LIVER
MAMMALS
MATERIALS
MICE
NUCLEIC ACIDS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANS
RATS
RNA
RODENTS
TOXIC MATERIALS
TRANSFER RNA
TRANSFERASES
VERTEBRATES