Hemizygous males are hypersensitive to 5-fluorouracil compared to control flies.
Suppresses both the phenotypic effects and the female sterility of all r alleles; also suppresses the r phenocopying and lethal effects of 6-azauracil administration. Little or no dihydrouracil dehydrogenase activity. Thought to interfere with pyrimidine catabolism. Unable to degrade uracil and extremely sensitive to exogenous pyrimidine. Enhances the expression of dp and net and causes b flies to have very black bodies, darker than wild type, especially along the wing veins; forms synthetic lethals in combination with tt and whd.