%0 Journal Article
%T Quantification of the Spatial Organization of the Nuclear Lamina as a Tool for Cell Classification
%A Christiaan H. Righolt
%A Diana A. Zatreanu
%A Vered Raz
%J ISRN Molecular Biology
%D 2013
%R 10.1155/2013/374385
%X The nuclear lamina is the structural scaffold of the nuclear envelope that plays multiple regulatory roles in chromatin organization and gene expression as well as a structural role in nuclear stability. The lamina proteins, also referred to as lamins, determine nuclear lamina organization and define the nuclear shape and the structural integrity of the cell nucleus. In addition, lamins are connected with both nuclear and cytoplasmic structures forming a dynamic cellular structure whose shape changes upon external and internal signals. When bound to the nuclear lamina, the lamins are mobile, have an impact on the nuclear envelop structure, and may induce changes in their regulatory functions. Changes in the nuclear lamina shape cause changes in cellular functions. A quantitative description of these structural changes could provide an unbiased description of changes in cellular function. In this review, we describe how changes in the nuclear lamina can be measured from three-dimensional images of lamins at the nuclear envelope, and we discuss how structural changes of the nuclear lamina can be used for cell classification. 1. Composition of the Nuclear Lamina The nuclear envelope (NE) is a biostructure, which separates the nuclear and cytoplasmic parts of eukaryotic cells. The NE is a dynamic structure composed of the outer nuclear membrane (ONM) and the inner nuclear membrane (INM). The NE is embedded with nuclear pore proteins, through which molecules selectively pass to move between the nucleus and the cytoplasm. The nuclear membranes are bilipid structures supported by a network of proteins. Within the nucleus, the INM is underlined by the nuclear lamina, a dynamic filamentous protein network. The nuclear lamina has both regulatory and structural roles. The nuclear lamina is predominantly composed of lamins, which are dynamically anchored to the INM via posttranslational modifications. The molecular composition of the nuclear lamina has been previously discussed in several reviews [1, 2]. In brief, lamins are divided into A- and B-types (LMNA and LMNB, resp.) and play a central role in the integrity of the nuclear lamina. Both proteins bind to the chromatin at highly defined regions, creating a regulatory role for lamina-chromatic interaction [3]. While LMNB is constitutively expressed, the expression of LMNA is developmentally regulated, and expression levels differ between cell types. It has, therefore, been suggested that LMNA also plays a regulatory role [1, 2]. Silencing of LMNB causes dramatic changes in the LMNA meshwork, while LMNA
%U http://www.hindawi.com/journals/isrn.molecular.biology/2013/374385/