title: Ring-like distribution of constitutive heterochromatin in bovine senescent cells.
abstract: BACKGROUND
  Cells that reach "Hayflick limit" of proliferation, known as senescent cells, possess a particular type of nuclear architecture. Human senescent cells are characterized by the presence of highly condensed senescent associated heterochromatin foci (SAHF) that can be detected both by immunostaining for histone H3 three-methylated at lysine 9 (H3K9me3) and by DAPI counterstaining.
  
  
  METHODS
  We have studied nuclear architecture in bovine senescent cells using a combination of immunofluorescence and 3D fluorescent in-situ hybridization (FISH).
  
  
  RESULTS
  Analysis of heterochromatin distribution in bovine senescent cells using fluorescent in situ hybridization for pericentric chromosomal regions, immunostaining of H3K9me3, centromeric proteins CENP A/B and DNA methylation showed a lower level of heterochromatin condensation as compared to young cells. No SAHF foci were observed. Instead, we observed fibrous ring-like or ribbon-like heterochromatin patterns that were undetectable with DAPI counterstaining. These heterochromatin fibers were associated with nucleoli.
  
  
  CONCLUSIONS
  Constitutive heterochromatin in bovine senescent cells is organized in ring-like structures.
authors: INRA UMR 1198 Groupe Biologie du Développement et Reproduction, Jouy en Josas, France. karyolog@gmail.com
authors: Andrey
authors: A
authors: Pichugin
authors: Nathalie
authors: N
authors: Beaujean
authors: Xavier
authors: X
authors: Vignon
authors: Yegor
authors: Y
authors: Vassetzky
mesh_terms: D000818:Animals; D002417:Cattle; D002460:Cell Line; D016922:Cellular Senescence / Q000187:drug effects; D002503:Centromere / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006570:Heterochromatin / Q000378:metabolism*; D006877:Hydroxamic Acids / Q000494:pharmacology
chemical_list: D006570:Heterochromatin; D006877:Hydroxamic Acids; C012589:trichostatin A