Intranuclear network of 3-5 nm and 8-10 nm fibers in EL-4 lymphoma cells.
While much evidence indicates a high degree of spatial organization in the nucleus, the underlying molecular structures that support it remain poorly characterized. By extracting with high concentrations of RNase A in a modification of the sequential extraction protocol of Penman, we have identified a novel intranuclear network in the mouse lymphoma cell line, EL-4. Micrographs of embedment-free sections of extracted cells reveal anastomosing filaments of two different diameters: 3-5 nm and 8-10 nm. The 3-5-nm filaments are interconnected in many junctions and appear to blend smoothly into each other. The 8-10-nm fibers frequently split into two 3-5-nm filaments. Some 3-5-nm fibers appear to be connected at 90 degrees angles with the 8-10-nm fibers. All junctions are smooth with no apparent junction protein. Flow cytometric analysis of RNase A- (and DNase I-) extracted nuclear matrices indicates that they do not contain significant amounts of protein that react with anti-actin and anti-vimentin monoclonal antibodies. Extraction of EL-4 nuclear matrices with high salt does not reveal 8-10-nm core filaments described after similar treatment of tumor cell lines of cervical and mammary origin. The novel characteristics of the core filaments in EL-4 lymphoma cells may reflect cell-type specificity of the nuclear matrix.
Padros
M R
MR
Instituto de Fisiologia, BUAP, Puebla, Pue 72001, Mexico.
Giles
D M
DM
Suarez
M D
MD
D000199:Actins / Q000032:analysis / Q000276:immunology; D000818:Animals; D000918:Antibody Specificity; D005434:Flow Cytometry; D007381:Intermediate Filament Proteins / Q000032:analysis / Q000276:immunology; D008223:Lymphoma; D051379:Mice; D008854:Microscopy, Electron; D015530:Nuclear Matrix / Q000737:chemistry* / Q000276:immunology / Q000648:ultrastructure*; D012313:RNA / Q000502:physiology; D014407:Tumor Cells, Cultured / Q000648:ultrastructure
D000199:Actins; D007381:Intermediate Filament Proteins; D012313:RNA