Heterochromatin usually is sequestered near the periphery and the nucleoli in mammalian nuclei. However, in terminally differentiated retinal rod cells of nocturnal mammals, heterochromatin instead accumulates in the interior, to give a so-called inside-out nuclear architecture. Solovei et al. now reports that in most cells, the lamin B receptor mediates peripheral localization early during development and that lamin A/C then takes over this tethering function during terminal differentiation. Furthermore, they show that the unique architecture of the nocturnal animal rod cell is caused by the absence of both tethers and can be phenocopied in LBR/lamin A/C double knockouts.
I Solovei, AS Wang, K Thanisch, CS Schmidt, S Krebs, M Zwerger, TV Cohen, D Devys, R Foisner, L Peichl, H Herrmann, H Blum, D Engelkamp, CL Stewart, H Leonhardt, B Joffe. LBR and lamin A/C sequentially tether peripheral heterochromatin and inversely regulate differentiation. Cell 2013; 152: 584- 98.
PMID: 23374351 DOI: 10.1016/j.cell.2013.01.009