GSE111032 Heterochromatin drives organization of conventional and inverted nuclei

Contributors : Martin Falk ; Yana Feodorova ; Natasha Naumova ; Maxim Imakaev ; Bryan Lajoie ; Heinrich Leonhardt ; Boris Joffe ; Job Dekker ; Fudenberg Geoffrey ; Irina Solovei ; Mirny LeonidSeries Type : OtherOrganism : Mus musculusThe mammalian cell nucleus displays a remarkable spatial segregation of active euchromatic from inactive heterochromatic genomic regions. In conventional nuclei, euchromatin is localized in the nuclear interior and heterochromatin at the nuclear periphery. In contrast, rod photoreceptors in nocturnal mammals have inverted nuclei, with a dense heterochromatic core and a thin euchromatic outer shell. This inverted architecture likely converts rod nuclei into microlenses to facilitate nocturnal vision, and may relate to the absence of particular proteins that tether heterochromatin to the lamina. However, both the mechanism of inversion and the role of interactions between different types of chromatin and the lamina in nuclear organization remain unknown. To elucidate this mechanism we performed Hi-C and microscopy on cells with inverted nuclei and their conventional counterparts. Strikingly, despite the inversion evident in microscopy, both types of nuclei display similar Hi-C maps. To resolve this paradox we developed a polymer model of chromosomes and found a universal mechanism that reconciles Hi-C and microscopy for both inverted and conventional nuclei. Based solely on attraction between heterochromatic regions, this mechanism is su...

Source: GEO: Gene Expression Omnibus - February 22, 2019 Category: Genetics & Stem Cells Tags: Other Mus musculus Source Type: research