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Pfleghaar K.B.,Anthropology and Human Genetics | Taimen P.,University of Turku | Butin-Israeli V.,Northwestern University | Shimi T.,Northwestern University | And 5 more authors.
Nucleus | Year: 2015

More than 20 mutations in the gene encoding A-type lamins (LMNA) cause progeria, a rare premature aging disorder. The major pathognomonic hallmarks of progeria cells are seen as nuclear deformations or blebs that are related to the redistribution of A- and B-type lamins within the nuclear lamina. However, the functional significance of these progeria-associated blebs remains unknown. We have carried out an analysis of the structural and functional consequences of progeria-associated nuclear blebs in dermal fibroblasts from a progeria patient carrying a rare point mutation p.S143F (C428T) in lamin A/C. These blebs form microdomains that are devoid of major structural components of the nuclear envelope (NE)/lamina including B-type lamins and nuclear pore complexes (NPCs) and are enriched in A-type lamins. Using laser capture microdissection and comparative genomic hybridization (CGH) analyses, we show that, while these domains are devoid of centromeric heterochromatin and gene-poor regions of chromosomes, they are enriched in gene-rich chromosomal regions. The active form of RNA polymerase II is also greatly enriched in blebs as well as nascent RNA but the nuclear co-activator SKIP is significantly reduced in blebs compared to other transcription factors. Our results suggest that the p.S143F progeria mutation has a severe impact not only on the structure of the lamina but also on the organization of interphase chromatin domains and transcription. These structural defects are likely to contribute to gene expression changes reported in progeria and other types of laminopathies. © 2015 Taylor & Francis Group, LLC.

Hubner B.,Anthropology and Human Genetics | Cremer T.,Anthropology and Human Genetics | Neumann J.,Anthropology and Human Genetics
Methods in Molecular Biology | Year: 2013

The term correlative microscopy denotes the sequential visualization of one and the same cell using various microscopic techniques. Correlative microscopy provides a unique platform to combine the particular strength of each microscopic approach and compensate for its specifi c limitations. As an example, we report results of a correlative microscopic study exploring features of the nuclear landscape in HeLa cells. We present a detailed protocol to fi rst investigate distinct structural features of a living cell in space and time (4D) using spinning disk laser scanning microscopy (SDLSM). Then, after fi xation and staining of selected structures (e.g., by means of immunodetection), details of these structures are explored at increasingly higher resolution using three-dimensional (3D) confocal laser scanning microscopy (CLSM); superresolution fl uorescence microscopy, such as three-dimensional structured illumination microscopy (3D-SIM); and transmission electron microscopy (TEM). We discuss problems involved in the comparison of images of a given cell nucleus recorded with different microscopic approaches, which requires not only a compensation for different resolutions but also for various distortions. © Springer Science+Business Media, LLC 2013.

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