The hiiragi gene encodes a poly(A) polymerase, which controls the formation of the wing margin in Drosophila melanogaster

The hiiragi (hrg) gene plays a key role in the development of the wing marg in in Drosophila melanogaster. A mutation in the hrg gene resulted in a dec rease in the level of the hrg transcript and was associated with a notched wing phenotype. We report here that the hrg gene encodes a poly(A) polymera se (PAP). The bovine cDNA for PAP type II reversed the phenotype due to mut ation of the hrg gene, suggesting that hrg might encode a functional homolo g of PAP. A mutation that reduced the enzymatic activity of Hrg failed to r everse the phenotype of hrg mutants, suggesting that the enzymatic activity of Hrg was required to rescue the wing phenotype. The levels of expression of wingless and cut at the presumptive wing margins were reduced in the la te third-instar larvae of hrg mutants. These results suggest that the produ ct of hrg is required for the normal expression of a series of genes in thi s region. Our results provide the first evidence that a PAP in Drosophila p lays a key role in the early development of the wing margin, acting to regu late the specific expression of a series of genes via, perhaps, control of the processing of the 3 ' ends of transcripts. (C) 2001 Academic Press.