SOME BIOCHEMICAL FACTORS IN X-RAY-INDUCED MUTATION IN BACTERIA

Journal Article · Thu Jun 01 04:00:00 EDT 1961 · Genetics (U.S.)

OSTI ID:4090774

Kada, T; Doudney, C O; Haas, F L

RNA or protein synthesis are effective in lowering markedly the mutation frequency response to uv light. Evidence indicates that DNA synthesis is the terminal event in UVinduced mutation, but that phenotypic expression of the genetic change involves protein synthesis subsequent to DNA synthesis. About half of the x-ray-induced reversions of the tryptophan requiring auxotroph, E. coli strain Wp2, are lost, when the culture is incubated for 50 minutes with chloramphenicol or 6-azauracil, sgents which block RNA or protein synthesis. A short period of incubation following x-ray exposure before addition of chloramphenicol or 6-azauracil is necessary for development of the chloramphenicol or 6-azauracil sensitivity of the mutations. These mutations require RNA synthesis, protein synthesis, and DNA synthesis for induction in a manner comparsble to UV-induced reversion. The other half of the x-ray-induced mutations are not lost when incubated with chloramphenicol or 6-azauracil for 50 minutes prior to plating on tryptophan containing medium. These mutations are completely expressed when plated on minimal medium without tryptophan after a short period of incubation in tryptophsn containing medium and before measurable DNA synthesis in the culture occurs. Expression does not occur in the presence of 6-azauracil or chloramphenicol. In the case of a thymineless, tyrosineless polyauxotroph, expression of the tyrosine reversion occurs in the absence of thymine for one half of the mutations while the other half requires thymine for expression. With half of the mutations which can take place in the absence of thymine, the functional reversion is produced by the x-ray in the gene, without the necessity of DNA replication, but that RNA and protein synthesis is required for gene action in phenotypic expression of the reverted character. (auth)

• Research Organization: Univ. of Texas M.D. Anderson Hospital and Tumor Inst., Houston
• NSA Number: NSA-15-020591
• OSTI ID: 4090774
• Journal Information: Genetics (U.S.), Journal Name: Genetics (U.S.) Vol. Vol: 46; ISSN GENTA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AMINO ACIDS
ANTIBIOTICS
BACTERIA
BIOCHEMISTRY
BIOLOGY AND MEDICINE
BIOSYNTHESIS
MUTATIONS
PROTEINS
RADIATION EFFECTS
RIBONUCLEIC ACID
ULTRAVIOLET RADIATION
X RADIATION