Hayashi S, Hirose S, Metcalfe T, Shirras A D
DNA Research Center, National Institute of Genetics, Shizuoka-ken, Japan.
Development. 1993 May;118(1):105-15. doi: 10.1242/dev.118.1.105.
Mutations in the escargot (esg) locus, which codes for a zinc-finger-containing protein with similarity to the product of the snail gene, cause a variety of defects in adult structures such as loss of abdominal cuticle and malformation of the wings and legs. esg RNA is expressed in wing, haltere, leg and genital imaginal discs and in abdominal histoblast nests in the embryo. Expression in imaginal tissues is also found in third instar larvae. In esg mutant larvae, normally diploid abdominal histoblasts replicate their DNA without cell division and become similar in appearance to the polytene larval epidermal cells. A similar phenotype was also found in imaginal discs of larvae mutant for both esg and the Drosophila raf gene. These results suggest that one of the normal functions of esg may be the maintenance of diploidy in imaginal cells.
蜗牛（esg）基因座发生突变，该基因座编码一种含锌指蛋白，与蜗牛基因的产物相似，会导致成虫结构出现各种缺陷，如腹部表皮缺失以及翅膀和腿部畸形。esg RNA在翅膀、平衡棒、腿部和生殖器成虫盘以及胚胎中的腹部组织母细胞巢中表达。在三龄幼虫的成虫组织中也发现了这种表达。在esg突变体幼虫中，正常的二倍体腹部组织母细胞在不进行细胞分裂的情况下复制其DNA，并在外观上变得与多线幼虫表皮细胞相似。在esg和果蝇raf基因均突变的幼虫的成虫盘中也发现了类似的表型。这些结果表明，esg的正常功能之一可能是维持成虫细胞中的二倍体状态。
