The Nucleus
The nucleus is the largest of the cellular compartments, housing the chromosomes with the vast majority of the cellular genome and multiple molecular machineries necessary for gene organization and expression. In recent years, contemporarily with the succ
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factors engaged in mRNA splicing. It is suggested that IGs represent sites of storage and/or assembly of splicing complexes. IGs also contain multiple RNA processing factors, transcription factors, and potential structural proteins, such as lamins. Both chromatin proteins and proteins of interchromatin domains reside only temporarily on chromatin and the respective compartments, and there is a continuous exchange with the nucleoplasm. The Cajal body (CB), first described by Ramon y Cajal a century ago, is the best characterized of the small nuclear bodies. It corresponds to the “coiled body” and was recently renamed after its discoverer. In Cajal bodies, components of transcription and RNA processing machineries are transiently localized (cf. Fig. 10).
References Cardoso MC, Schneider K, Martin RM, Leonhardt H (2012) Structure, function and dynamics of nuclear subcompartments. Curr Opin Cell Biol 24:79 Cau P, Navarro C, Harhouri K, Roll P, Sigaudy S, Kapsi E, Perrin S, De Sandre-Giovanolli A, Lévy N (2014) Nuclear matrix, nuclear envelope and premature aging syndromes in a translational research perspective. Semin Cell Developm Biol 29:125 Cremer T, Cremer C (2001) Chromosome territories, nuclear architecture and gene regulation in mammalian cells. Nat Rev Genetics 2:292 Derenzini M, Olins AL, Olins DE (2014) Chromatin structure in situ: the contribution of DNA ultrastructural cytochemistry. Eur J Histochem 58:2307 Iborra FJ, Jackson DA, Cook PR (2001) Coupled transcription and translation within nuclei of mammalian cells. Science 293:1139 Lamond AI, Spector DL (2003) Nuclear speckles: a model for nuclear organelles. Nat Rev Mol Cell Biol 4:605 Misteli T (2008) Physiological importance of RNA and protein mobility in the cell nucleus. Histochem Cell Biol 129:5 Pederson T (2002) Dynamics and genome-centricity of inter chromatin domains in the nucleus. Nat Cell Biol 4:E287 Pederson T (2013) The persistent plausibility of protein synthesis in the nucleus. Curr Opin Cell Biol 25:520 Rapkin LM, Anchel DRP, Li R, Bazett-Jones DP (2012) A view of the chromatin landscape. Micron 43:150 Roix J, Misteli T (2002) Genomes, proteoms, and dynamic networks in the cell nucleus. Histochem Cell Biol 118:105 Rouchette J, Genoud C, Vazquez-Nin GH, Kraus B, Cremer Th, Fakan S (2009) Revealing the high-resolution three-dimensional network of chromatin and interchromatin space: A novel electron-microscopic approach to reconstructing nuclear architecture. Chromos Res 17:801
Magnification: ×24,000 (A), ×106,000 (B) M. Pavelka, J. Roth, Functional Ultrastructure: Atlas of Tissue Biology and Pathology, Third Edition, DOI 10.1007/978-3-7091-1830-6_2, © Springer-Verlag Vienna 2015
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The Nucleus
VARIATION OF NUCLEAR SHAPE AND SIZE The shape and size of the nucleus in interphase can vary depending on the cell type and cellular activity. Nuclear shape and functional changes depend on nuclear lamins and on microtubules, while nuclear size seems to be primarily determined by the cytoplasmic volume, the karyoplasmic ratio. On t
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