title: Chromosome territory repositioning induced by PHA-activation of lymphocytes: A 2D and 3D appraisal.
abstract: BACKGROUND
  Genomes and by extension chromosome territories (CTs) in a variety of organisms exhibit nonrandom organization within interphase nuclei. CTs are susceptible to movement upon induction by a variety of stimuli, including: cell differentiation, growth factors, genotoxic agents, proliferating status, and stimulants that induce novel transcription profiles. These findings suggest nuclear architecture can undergo reorganization, providing support for a functional significance of CT organization. The effect of the initiation of transcription on global scale chromatin architecture has been underexplored. This study investigates the organization of all 24 human chromosomes in lymphocytes from two individuals in resting and phytohaemagglutinin activated lymphocytes using 2D and 3D approaches.
  
  
  RESULTS
  The radial organization of CTs in lymphocytes in both resting and activated lymphocytes follows a gene-density pattern. However, CT organization in activated nuclei appears less constrained exhibiting a more random organization. We report differences in the spatial relationship between homologous and heterologous CTs in activated nuclei. In addition, a reproducible radial hierarchy of CTs was identified and evidence of a CT repositioning was observed in activated nuclei using both 2D and 3D approaches.
  
  
  CONCLUSIONS
  Alterations between resting and activated lymphocytes could be adaptation of CTs to the new transcription profile and possibly the formation of new neighborhoods of interest or interaction of CTs with nuclear landmarks. The increased distances between homologous and heterologous CTs in activated lymphocytes could be a reflection of a defensive mechanism to reduce potential interaction to prevent any structural chromosome abnormalities (e.g. translocations) as a result of DNA damage that increases during lymphocyte activation.
authors.affiliation: Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199 USA.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Ioannou
authors.affiliation: Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199 USA ; Present address Centre for Cellular and Molecular Biology (CCMB), Council of Scientific and Industrial Research (CSIR) Uppal Road, Hyderabad, 500 007 India.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Kandukuri
authors.affiliation: Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199 USA.
authors.forename: Joe Leigh
authors.initials: JL
authors.lastname: Simpson
authors.affiliation: Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199 USA ; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199 USA.
authors.forename: Helen Ghislaine
authors.initials: HG
authors.lastname: Tempest
keywords: Chromosome territories; Genome organization; Phytohaemagglutinin; Repositioning