Dm-myb mutant lethality in Drosophila is dependent upon mip130:: positive and negative 1667 regulation of DNA replication
Dm-myb mutant lethality in Drosophila is dependent upon mip130:: positive and negative 1667 regulation of DNA replication
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DOI：
10.1101/gad.1206604
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发表时间：
2004-07-15
影响因子：
10.5
通讯作者：
Botchan, MR
中科院分区：
文献类型：
--
作者：
Beall, EL;Bell, M;Botchan, MR
果蝇卵泡细胞绒毛膜位点的基因扩增是DNA复制发育调控的一个模型。先前，我们发现Myb癌蛋白家族（DmMyb）的果蝇同源物与另外四个蛋白紧密相关，并且DmMyb是这种复制介导的扩增所必需的。在这里，我们使用靶向诱变技术在DmMyb复合物的最大亚基，Aly和Lin-9家族成员，myb相互作用蛋白130 （Mip130）中产生突变。我们发现，在基因扩增阶段，mip130突变雌性不育，并且在整个卵泡细胞核中表现出不适当的溴脱氧嘧啶（BrdU）掺入。Dm-myb突变是致命的，而mip130突变是可存活的。令人惊讶的是，Dm-myb mip130双突变体也能存活，并表现出与单独的mip130突变体相同的表型。这表明，没有DmMyb对抗作用的Mip130活性可能是Dm-myb突变体致死性的原因。RNA干扰（RNAi）选择性地去除每个DmMyb复合体成员表明，DmMyb蛋白水平依赖于几个复合体成员的存在。综上所述，这些数据支持DmMyb激活含有Mip130的抑制复合体的模型，使其能够以暂时和发育受限的方式支持特定位点的复制。
Gene amplification at the chorion loci in Drosophila ovarian follicle cells is a model for the developmental regulation of DNA replication. Previously, we showed that the Drosophila homolog of the Myb oncoprotein family (DmMyb) is tightly associated with four additional proteins and that DmMyb is required for this replication-mediated amplification. Here we used targeted mutagenesis to generate a mutant in the largest subunit of the DmMyb complex, the Aly and Lin-9 family member, Myb-interacting protein 130 (Mip130). We found that mip130 mutant females are sterile and display inappropriate bromodeoxymidine (BrdU) incorporation throughout the follicle cell nuclei at stages undergoing gene amplification. Whereas mutations in Dm-myb are lethal, mutations in mip130 are viable. Surprisingly, Dm-myb mip130 double mutants are also viable and display the same phenotypes as mip130 mutants alone. This suggests that Mip130 activity without DmMyb counteraction may be responsible for the Dm-myb mutant lethality. RNA interference (RNAi) to selectively remove each DmMyb complex member revealed that DmMyb protein levels are dependent upon the presence of several of the complex members. Together, these data support a model in which DmMyb activates a repressive complex containing Mip130 into a complex competent to support replication at specific loci in a temporally and developmentally proscribed manner.