Three-Dimensional Arrangement of Genes Involved in Lipid Metabolism in Nuclei of Porcine Adipocytes and Fibroblasts in Relation to Their Transcription Level

Abstract

The 3-dimensional arrangement of chromosomes and genes within a nuclear space is considered to represent the level of transcriptional regulation. Understanding how the nuclear architecture of adipocyte cells contributes to gene expression has become the subject of greatinterest in the context of obesity research. In this study we investigated nuclear positioning of 3 gene loci involved in lipid metabolism in the pig (Sus scrofa, SSC) which is considered as an important animal model for obesity in humans. We found that the position of the SCD gene in the 3-dimensional space of the cell nucleus is not correlated with transcriptional activity. The gene locus as well as chromosome territory SSC14 occupied the same peripheral location in adipocyte and fibroblast cells, in spite of the fact that their transcription level differs significantly between both cell types. For the 2 other investigated genes, i.e. ACACA and SREBF1 and their chromosome territory (SSC12), slightly different nuclear locations were found. They occupied intermediate nuclear positions in fibroblast nuclei, while in adipocytes they were positioned in the nuclear interior. The more internal location of these genes corresponds to increased transcription levels in fat cells. Our results confirm the non-random position of genes and chromosome territories in nuclei of adult porcine cells and indicate that relationship between transcription activity and gene positioning exists only for some but not all genes.

Characterisation of Nuclear Architectural Alterations during In Vitro Differentiation of Human Stem Cells of Myogenic Origin

“…A number of studies support the importance of chromosome position in the interphase nuclei with relation to gene expression [25] [26]. The correlations between the expression profile and modification of epigenetic status of chromatin are often mentioned with reference to nuclear architecture.…”

Nuclear organization during in vitro differentiation of porcine mesenchymal stem cells (MSCs) into adipocytes

“…Chromosomes were counterstained with DAPI in the Vectashield medium (Vector Laboratories). To verify specificity of the telomere signals, hybridization was also performed on metaphase spreads derived from the fibroblast cell culture established for the pig as described earlier by Kociucka et al (2012).…”

“…Nuclei were segmented from Z-stacks using nucleus edge detector function, while studied nuclear structures were segmented using hysteresis segmenter function. The radial position of the studied structures was evaluated as described earlier by Kociucka et al (2012). Briefly, the ratio of measurement distance was calculated, where R was a distance from the signal to the nucleus center divided by distance from the signal to the nuclear border.…”

“…Recently, the role of nuclear organization during adipocyte differentiation has been focused; however, comparing to other cellular processes, this research is still in infancy (Charo et al 2016). The most important events taking place during adipogenesis include: reorganization of nuclear lamin (Verstraeten et al 2011), changes in the nuclear position of chromosome territories and individual genes (Kociucka et al 2012;Kuroda et al 2004;Szczerbal et al 2009), association of adipogenic genes with nuclear speckles (Szczerbal and Bridger 2010), and interactions between selected adipogenic promoters (LeBlanc et al 2014). These studies were performed using different cell lines and organisms (human, mouse, rat, and pig), and to date, they have provided no comprehensive characterization of nuclear organization for each species.…”

Three-Dimensional Positioning of B Chromosomes in Fibroblast Nuclei of the Red Fox and the Chinese Raccoon Dog

“…The nuclear position of FISH signals was assessed using NEMO software, developed to visualize and analyze 3D-FISH images [Iannuccelli et al, 2010]. Image analysis was performed as previously described by Kociucka et al [2012]. Briefly, the radial position of gene signals was determined by the ratio of measurement distance from the FISH signal to the nucleus center by distance from the FISH signal to the nuclear border ( R value).…”