[Enhancer-of-white-apricot and its effects on the copia insertion allele white-apricot in Drosophila melanogaster].

In Drosophila melanogaster, the w(a) allele differs from the red-eye gene (w+) by the insertion of the retrovirus-like transposable element copia within the transcription unit. The w(a) flies have the apricot eye color. Most RNAs derived from w(a) have 3' termini within the 3' LTR of copia, and only small amounts of structurally normal RNA are produced. The eye color of flies with w(a) is affected by the gene Enhancer-of-white-apricot [E(w(a))] and become lighter. This effect on pigmentation is correlated with a corresponding decrease in white RNA having wild-type structure which was determined by the Northern blot. Three revertant alleles of E(w(a)) was generated by the irradiation with gamma-ray. These alleles are recessive lethals with death occurring during the larval stage. The original E(w(a)) allele is an antimorph and produces a product that interferes with the activity of the wild-type gene which have the product expected to either have a positive role in the splicing of w(a) RNAs or a negative role in polyadenylation.