Isolation and characterization of amber suppressors in yeast

Journal Article · Sun Feb 01 04:00:00 EST 1976 · Genetics, v. 82, no. 2, pp. 251-272

OSTI ID:4023278

Liebman, S W; Sherman, F; Stewart, J W

Nonsense suppressors were obtained in a haploid yeast strain containing eight nutritional mutations, that are assumed to be amber or ochre, and the cycl- 179 amber mutation that has a UAG codon corresponding to position 9 in iso-1- cytochrome c. Previous studies established that the biosynthesis and function of iso-l-cytochrome c is compatible with replacements at position 9 of amino acids having widely different structures. UV-induced revertants, selected on media requiring the reversion of one or two of the amber nutritional markers, were presumed to contain a suppressor if there was the unselected reversion of at least one other marker. The 1088 suppressors that were isolated could be divided into 78 phenotypic classes. Only 43 suppressors of three classes caused the production of more than 50 percent of the normal amount of iso-l-cytochrome c in the cycl-179 strain. Genetic analyses indicated that all of these highly efficient amber suppressors are allelic to one or another of the eight suppressors which cause the insertion of tyrosine at ochre (UAA) codons. Furthermore, only tyrosine has been identified at position 9 in iso-l-cytochrome c in cycl-179 strains suppressed with these efficient amber suppressors. (auth)

• Research Organization: Univ. of Rochester School of Medicine and Dentistry, NY
• NSA Number: NSA-33-026158
• OSTI ID: 4023278
• Journal Information: Genetics, v. 82, no. 2, pp. 251-272, Journal Name: Genetics, v. 82, no. 2, pp. 251-272; ISSN GENTA
• Country of Publication: United States
• Language: English

Related Subjects

*CYTOCHROMES-- BIOSYNTHESIS
*GENE RECOMBINATION-- RADIOINDUCTION
*MUTATIONS-- RADIOINDUCTION
*SACCHAROMYCES CEREVISIAE-- MUTATIONS
560131* --Biomedical Sciences
Applied Studies--Radiation Effects--Radiation Effects on Microorganisms--Basic Studies
AMINO ACIDS
BIOLOGICAL RADIATION EFFECTS
N48310* --Life Sciences--Radiation Effects on Microorganisms- -Basic Studies
ULTRAVIOLET RADIATION
X RADIATION