Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA.
Nat Commun. 2013;4:1464. doi: 10.1038/ncomms2469.
Myc has been characterized as a transcription factor that activates expression of genes involved in pluripotency and cancer, and as a component of the replication complex. Here we find that Myc is present at promoters and enhancers of Drosophila melanogaster genes during interphase. Myc colocalizes with Orc2, which is part of the prereplication complex, during G1. As is the case in mammals, Myc associates preferentially with paused genes, suggesting that it may also be involved in the release of RNA polymerase II from the promoter-proximal pausing in Drosophila. Interestingly, about 40% of Myc sites present in interphase persists during mitosis. None of the Myc mitotic sites correspond to enhancers, and only some correspond to promoters. The rest of the mitotic Myc sites overlap with binding sites for multiple insulator proteins that are also maintained in mitosis. These results suggest alternative mechanisms to explain the role of Myc in pluripotency and cancer.
Myc 已被描述为一种转录因子，它可以激活参与多能性和癌症的基因的表达，并作为复制复合物的一部分。在这里，我们发现 Myc 存在于果蝇基因的启动子和增强子上，处于间期。在 G1 期，Myc 与 Orc2 共定位，Orc2 是复制前复合物的一部分。与哺乳动物的情况一样，Myc 优先与暂停的基因结合，这表明它也可能参与 RNA 聚合酶 II 从果蝇启动子近端暂停的释放。有趣的是，大约 40%存在于间期的 Myc 位点在有丝分裂期间持续存在。有丝分裂期间的 Myc 位点都不对应增强子，只有一些对应启动子。其余的有丝分裂 Myc 位点与多种绝缘子蛋白的结合位点重叠，这些绝缘子蛋白在有丝分裂中也被保留下来。这些结果表明了可以解释 Myc 在多能性和癌症中的作用的替代机制。
