Drosophila hyperplastic discs encodes and E6-AP type ubiquitin protein ligase involved in cell proliferation control.

果蝇增生性视盘(BYD)基因的产物HIT是调节成像性视盘细胞增殖和图案形成所必需的。序列比较表明，Hyd含有一个与人乳头瘤病毒蛋白E6-P相关的细胞蛋白E6-AP的催化结构域，E6-E6-P具有泛素蛋白连接酶活性。作为Hyd与E6-P功能相似的证据，我们证明了Hyd与由bend基因编码的果蝇泛素结合酶结合，并在依赖于该E2酶的反应中与泛素形成硫代酯。编码泛素活化酶的基因的突变，在无止境中，以及在编码蛋白酶体成分fins26的基因中，增强了hyd突变的表型，这表明这些基因的产物共同作用，控制泛素素以及随后在果蝇成像盘中细胞增殖和图案形成所需的蛋白质的降解。

The product of the hyperplastic discs (byd) gene of Drosophila, HIT, is required for regulating imaginal disc cell proliferation and pattern formation. Sequence comparisons revealed that HYD contains a region similar to the putative catalytic domain of E6-AP, a cellular protein that associates with a human papillomavirus protein of E6-P, E6-E6-P has ubiquitin-protein ligase activity. As evidence that HYD is functionally similar to E6-P, we show that HYD associates with a Drosophila ubiquitin conjugating enzyme encoded by the bendless gene and that HYD forms a thioester with ubiquitin in a reaction dependent on this E2 enzyme. Mutation in the gene encoding an ubiquitin activating enzyme, in bendless, and in a gene encoding a proteasome component fins26, enhance the phenotype of hyd mutations suggesting that the products of these genes work together to control ubiquitinatin and subsequent degradation of proteins required for cell proliferation and pattern formation in Drosophila imaginal discs.