Genetics, Vol 126, 625-637, Copyright © 1990


INVESTIGATIONS

Drosophila Nonsense Suppressors: Functional Analysis in Saccharomyces cerevisiae, Drosophila Tissue Culture Cells and Drosophila melanogaster

D. Garza, M. M. Medhora and D. L. Hartl
Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110-1095

Amber (UAG) and opal (UGA) nonsense suppressors were constructed by oligonucleotide site-directed mutagenesis of two Drosophila melanogaster leucine-tRNA genes and tested in yeast, Drosophila tissue culture cells and transformed flies. Suppression of a variety of amber and opal alleles occurs in yeast. In Drosophila tissue culture cells, the mutant tRNAs suppress hsp70:Adh (alcohol dehydrogenase) amber and opal alleles as well as an hsp70:{beta}-gal ({beta}-galactosidase) amber allele. The mutant tRNAs were also introduced into the Drosophila genome by P element-mediated transformation. No measurable suppression was seen in histochemical assays for Adh(n4) (amber), Adh(nB) (opal), or an amber allele of {beta}-galactosidase. Low levels of suppression (approximately 0.1-0.5% of wild type) were detected using an hsp70:cat (chloramphenicol acetyltransferase) amber mutation. Dominant male sterility was consistently associated with the presence of the amber suppressors.