A subset of Drosophila Myc sites remain associatedwith mitotic chromosomes colocalized withinsulator proteins

摘要

Myc has been characterized as a transcription factor that activates expression of genesinvolved in pluripotency and cancer, and as a component of the replication complex. Here wefind that Myc is present at promoters and enhancers of Drosophila melanogaster genes duringinterphase. 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 thatit may also be involved in the release of RNA polymerase II from the promoter-proximalpausing in Drosophila. Interestingly, about 40% of Myc sites present in interphase persistsduring mitosis. None of the Myc mitotic sites correspond to enhancers, and only somecorrespond to promoters. The rest of the mitotic Myc sites overlap with binding sitesfor multiple insulator proteins that are also maintained in mitosis. These results suggestalternative mechanisms to explain the role of Myc in pluripotency and cancer.