Association of DNAse hypersensitive chromatin domains with the nuclear envelope and with nuclear pore complexes in 3T3 fibroblasts
Year: 1999
Type: dissertation
Abstract: DNAse hypersensitive chromatin (DHC), putative transcriptionally competent sequences, exists either as pan-nuclear speckles, or as a shell apposed to the nuclear envelope, in cells with "flat" or spheroidal nuclei respectively. We postulated that DHC also associated with the nuclear envelope in "flat" nuclei, but that such an association may not be resolvable, due to the interdigitation at the nuclear midplane, of DHC associated with the upper and lower nuclear surfaces respectively. 3T3 fibroblasts, characterized by "flat" nuclei, were therefore subjected to hypotonic expansion, followed by 'in situ' nick translation to visualize DHC. Confocal analysis of unexpanded cells showed that DHC is present as a shallow dome predominantly at the apical aspect of the nucleus, i.e. the side facing the culture medium. This topology persisted after hypotonic expansion and argues for a polarized association of DHC domains with the nuclear membrane. Preliminary data also indicate a similar, polarized distribution of nuclear pore complexes (NPCs). We conclude that the nuclear periphery may function as a compartment for the spatial coupling of transcription and nucleo-cytoplasmic transport.
Author: Jonathan Ka Lok Chan
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2625523596