PT  - JOURNAL ARTICLE
AU  - Hilbert, Lennart
AU  - Sato, Yuko
AU  - Kimura, Hiroshi
AU  - Jülicher, Frank
AU  - Honigmann, Alf
AU  - Zaburdaev, Vasily
AU  - Vastenhouw, Nadine L.
TI  - Transcription organizes euchromatin similar to an active microemulsion
AID  - 10.1101/234112
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 234112
4099  - http://biorxiv.org/content/early/2018/08/01/234112.short
4100  - http://biorxiv.org/content/early/2018/08/01/234112.full
AB  - Chromatin is organized into heterochromatin, which is transcriptionally inactive, and euchromatin, which can switch between transcriptionally active and inactive states. This switch in euchromatin activity is accompanied by changes in its spatial distribution. How euchromatin rearrangements are established is unknown. Here we use super-resolution and live-cell microscopy to show that transcriptionally inactive euchromatin moves away from transcriptionally active euchromatin. This movement is driven by the formation of RNA-enriched microenvironments that exclude inactive euchromatin. Using theory, we show that the segregation into RNA-enriched microenvironments and euchromatin domains can be considered an active microemulsion. The tethering of transcripts to chromatin via RNA polymerase II forms effective amphiphiles that intersperse the two segregated phases. Taken together with previous experiments, our data suggest that chromatin is organized in the following way: heterochromatin segregates from euchromatin by phase separation, while transcription organizes euchromatin similar to an active microemulsion.