Mediator and RNA polymerase II forms phase-separated bodies and colocalizes with centrosomes during mitosis.

In interphase, transcriptional proteins such as RNA polymerase II and Mediator are known to form phase-separated bodies to regulate an expression level of SE-controlled genes. However, a behavior of such proteins during mitosis, a cell cycle stage in which most transcriptional activities are silent, is still poorly understood. Here, we show that RNA polymerase II and Mediator form phase-separated bodies during mitosis. Unlike condensates in interphase which are formed based on clustered enhancer elements, condensates in mitosis are formed based on pericentriolar materials, which are phase-separated bodies in mitosis. We suggest that centrosomes play a role of not only microtubule-organizing centers but also protein storages for immediate transcriptional activities after mitosis.