Murata T, Nagaso H, Kashiwabara S, Baba T, Okano H, Yokoyama K K
RIKEN Tsukuba Institute, Tsukuba, Ibaraki, 305-0074, Japan.
Dev Biol. 2001 May 1;233(1):137-47. doi: 10.1006/dbio.2001.0205.
The hiiragi (hrg) gene plays a key role in the development of the wing margin in Drosophila melanogaster. A mutation in the hrg gene resulted in a decrease 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) polymerase (PAP). The bovine cDNA for PAP type II reversed the phenotype due to mutation of the hrg gene, suggesting that hrg might encode a functional homolog of PAP. A mutation that reduced the enzymatic activity of Hrg failed to reverse 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 late third-instar larvae of hrg mutants. These results suggest that the product of hrg is required for the normal expression of a series of genes in this region. Our results provide the first evidence that a PAP in Drosophila plays a key role in the early development of the wing margin, acting to regulate the specific expression of a series of genes via, perhaps, control of the processing of the 3' ends of transcripts.
平椹（hrg）基因在黑腹果蝇翅缘发育中起关键作用。hrg基因的突变导致hrg转录本水平降低，并与缺刻翅表型相关。我们在此报告，hrg基因编码一种聚腺苷酸聚合酶（PAP）。II型PAP的牛cDNA逆转了因hrg基因突变导致的表型，这表明hrg可能编码PAP的功能同源物。降低Hrg酶活性的突变未能逆转hrg突变体的表型，这表明Hrg的酶活性是挽救翅表型所必需的。在hrg突变体的三龄晚期幼虫中，假定翅缘处无翅基因和切断基因的表达水平降低。这些结果表明，hrg的产物是该区域一系列基因正常表达所必需的。我们的结果提供了首个证据，表明果蝇中的一种PAP在翅缘早期发育中起关键作用，可能通过控制转录本3'末端的加工来调节一系列基因的特异性表达。
