dDP is needed for normal cell proliferation
dDP is needed for normal cell proliferation
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DOI：
10.1128/mcb.25.8.3027-3039.2005
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发表时间：
2005-04-01
影响因子：
5.3
通讯作者：
Dyson, NJ
中科院分区：
文献类型：
--
作者：
Frolov, MV;Moon, NS;Dyson, NJ
为了深入了解E2 F的基本功能，我们研究了果蝇中E2 F和DP家族成员完全失活引起的表型。我们的研究结果表明，DDP需要dE 2F 1和dE 2F 2的DNA结合活性在体外和体内。在组织培养细胞和突变动物中，dE 2F和dDP蛋白的水平是强烈相互依赖的。在不存在DDP的情况下，dE 2F 1和dE 2F 2的水平显著下降，反之亦然。因此，靶向dDP引起的细胞周期和转录表型模拟靶向dE 2F 1和dE 2F 2的作用，并且与灭活所有三种蛋白质的作用不可区分。虽然反式杂合子dDP突变体动物发展到后期蛹阶段，体细胞突变体克隆的分析表明，dDP突变体细胞是在一个严重的增殖劣势时，直接与野生型邻居。引人注目的是，在dDP突变克隆中，S期进入或退出的时间并没有延迟，细胞周期蛋白A或细胞周期蛋白B的积累也没有延迟。然而，最大水平的溴脱氧尿苷掺入dDP突变体克隆减少，RNA干扰实验表明，dDP-耗尽的细胞容易停滞在S期。此外，dDP突变体克隆含有减少的有丝分裂细胞，表明dDP突变体细胞在G（2）/M期进展中存在缺陷。因此，DDP对于G（1）-到-S转变的发育控制不是必需的，但对于正常细胞增殖、最佳DNA合成和有效的G（2）/M进展是必需的。
To gain insight into the essential functions of E2F, we have examined the phenotypes caused by complete inactivation of E2F and DP family members in Drosophila. Our results show that dDP requires dE2F1 and dE2F2 for DNA-binding activity in vitro and in vivo. In tissue culture cells and in mutant animals, the levels of dE2F and dDP proteins are strongly interdependent. In the absence of dDP, the levels of dE2F1 and dE2F2 decline dramatically, and vice versa. Accordingly, the cell cycle and transcriptional phenotypes caused by targeting dDP mimic the effects of targeting both dE2F1 and dE2F2 and are indistinguishable from the effects of inactivating all three proteins. Although trans-heterozygous dDP mutant animals develop to late pupal stages, the analysis of somatic mutant clones shows that dDP mutant cells are at a severe proliferative disadvantage when compared directly with wild-type neighbors. Strikingly, the timing of S-phase entry or exit is not delayed in dDP mutant clones, nor is the accumulation of cyclin A or cyclin B. However, the maximal level of bromodeoxyuridine incorporation is reduced in dDP mutant clones, and RNA interference experiments show that dDP-depleted cells are prone to stall in S phase. In addition, dDP mutant clones contain reduced numbers of mitotic cells, indicating that dDP mutant cells have a defect in G(2)/M-phase progression. Thus, dDP is not essential for developmental control of the G(1)-to-S transition, but it is required for normal cell proliferation, for optimal DNA synthesis, and for efficient G(2)/M progression.