Isolation of temperature-sensitive diphtheria toxins in yeast and their effects on Drosophila cells.
We have isolated temperature-sensitive diphtheria toxins (DT-A(ts)) to develop a method that allows temporal impedement of cellular functions. Four DT-A(ts) genes were isolated in a mutagenesis screen using the yeast, Saccharomyces cerevisiae. When expressed in yeast, these DT-A(ts) arrest growth at 18 degrees C but not at 30 degrees C. Three DT-A(ts) were subsequently tested in the R1-R6 photoreceptor cells of transgenic fruit flies, Drosophila melanogaster. The toxins show similar temperature dependence in both organisms, suggesting that they may be useful in a wide range of non-homeothermic species. DNA sequence analysis revealed that three of the four DT-A(ts) mutations are novel. Interestingly, the fourth DT-A(ts) carries the same point mutation as the extensively characterized CRM197, an ADP ribosyltransferase-defective form of diphtheria toxin.
Bellen
H J
HJ
Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030.
D'Evelyn
D
D
Harvey
M
M
Elledge
S J
SJ
D000818:Animals; D016923:Cell Death; D004167:Diphtheria Toxin / Q000302:isolation & purification*; D004330:Drosophila; D005260:Female; D005798:Genes, Bacterial / Q000502:physiology*; D008297:Male; D008854:Microscopy, Electron; D016296:Mutagenesis; D010786:Photoreceptor Cells / Q000293:injuries / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D016415:Sequence Alignment; D013696:Temperature
D004167:Diphtheria Toxin