Callaghan M J, Russell A J, Woollatt E, Sutherland G R, Sutherland R L, Watts C K
Cancer Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, NSW, Australia.
Oncogene. 1998 Dec 31;17(26):3479-91. doi: 10.1038/sj.onc.1202249.
Use of the differential display technique to isolate progestin-regulated genes in T-47D human breast cancer cells led to identification of a novel gene, EDD. The cDNA sequence contains a 2799 amino acid open reading frame sharing 40% identity with the predicted 2894 amino acid product of the Drosophila melanogaster tumor suppressor gene hyperplastic discs, while the carboxy-terminal 889 amino acids show 96% identity to a rat 100 kDa HECT domain protein. EDD mRNA was progestin-induced in T-47D cells and was highly abundant in testes and expressed at moderately high levels in other tissues, suggesting a broad role for EDD. Anti-EDD antibodies immunoprecipitated an approximately 300 kDa protein from T-47D cell lysates. HECT family proteins function as E3 ubiquitin-protein ligases, targeting specific proteins for ubiquitin-mediated proteolysis. EDD is likely to function as an E3 as in vitro translated protein bound ubiquitin reversibly through a conserved HECT domain cysteine residue. EDD was localized by FISH to chromosome 8q22, a locus disrupted in a variety of cancers. Given the homology between EDD and the hyperplastic discs protein, which is required for control of imaginal disc growth in Drosophila, EDD potentially has a role in regulation of cell proliferation or differentiation.
利用差异显示技术在T-47D人乳腺癌细胞中分离孕激素调节基因，从而鉴定出一个新基因EDD。该cDNA序列包含一个2799个氨基酸的开放阅读框，与果蝇黑腹果蝇肿瘤抑制基因增生盘预测的2894个氨基酸产物有40%的同源性，而其羧基末端的889个氨基酸与大鼠100 kDa HECT结构域蛋白有96%的同源性。EDD mRNA在T-47D细胞中受孕激素诱导，在睾丸中高度丰富，在其他组织中也有中等程度的高表达，提示EDD具有广泛作用。抗EDD抗体从T-47D细胞裂解物中免疫沉淀出一种约300 kDa的蛋白质。HECT家族蛋白作为E3泛素蛋白连接酶，将特定蛋白质靶向泛素介导的蛋白水解。EDD可能作为一种E3发挥作用，因为体外翻译的蛋白通过保守的HECT结构域半胱氨酸残基可逆地结合泛素。通过荧光原位杂交将EDD定位到8号染色体q22区，该位点在多种癌症中发生破坏。鉴于EDD与增生盘蛋白之间的同源性，后者是果蝇成虫盘生长控制所必需的，EDD可能在细胞增殖或分化的调节中发挥作用。
