Ring-like distribution of constitutive heterochromatin in bovine senescent cells

Andrey Pichugin (1, 2) , Nathalie Beaujean (1) , Xavier Vignon (1) , Yegor Vassetzky (2)

1 BDR - Biologie du développement et reproduction
2 IMC (UMR 8126) - Interactions moléculaires et cancer

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.

Mots clés: nuclear architecture; heterochromatin; DNA methylation; bovine senescent; multidisciplinary sciences; science and technology

Domaines: Biologie du développement

Andrey Pichugin, Nathalie Beaujean, Xavier Vignon, Yegor Vassetzky. Ring-like distribution of constitutive heterochromatin in bovine senescent cells. PLoS ONE, 2011, 6 (11), pp.1-7. ⟨10.1371/journal.pone.0026844⟩. ⟨hal-01019386⟩