The integrity of a lamin-B1-dependent nucleoskeleton is a fundamental determinant of RNA synthesis in human cells.
Spatial organisation of nuclear compartments is an important regulator of chromatin function, yet the molecular principles that maintain nuclear architecture remain ill-defined. We have used RNA interference to deplete key structural nuclear proteins, the nuclear lamins. In HeLa cells, we show that reduced expression of lamin B1, but not lamin A/C, severely inhibits RNA synthesis--first by RNA polymerase II and later by RNA polymerase I. Declining levels of transcription correlate with different morphological changes in major nuclear compartments, nucleoli and nuclear speckles. Ultimately, nuclear changes linked to the loss of synthetic activity result in expansion of the inter-chromatin domain and corresponding changes in the structure and spatial organisation of chromosome territories, which relocate towards the nuclear periphery. These results show that a lamin B1-containing nucleoskeleton is required to maintain RNA synthesis and that ongoing synthesis is a fundamental determinant of global nuclear architecture in mammalian cells.
Tang
Chi W
CW
Faculty of Life Sciences, University of Manchester, MIB, 131 Princess Street, Manchester, M1 7DN, UK.
Maya-Mendoza
Apolinar
A
Martin
Catherine
C
Zeng
Kang
K
Chen
Songbi
S
Feret
Dorota
D
Wilson
Stuart A
SA
Jackson
Dean A
DA
D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D034904:Lamin Type A / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D034921:Lamin Type B / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D008856:Microscopy, Fluorescence; D015530:Nuclear Matrix / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis* / Q000235:genetics; D034622:RNA Interference; D012318:RNA Polymerase I / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism
D034904:Lamin Type A; D034921:Lamin Type B; C440308:lamin C; D012313:RNA; D012319:RNA Polymerase II; D012318:RNA Polymerase I