Scientific article

The Dynamics of Yeast Telomeres and Silencing Proteins through the Cell Cycle

Published inJournal of Structural Biology, vol. 129, no. 2-3, p. 159-174
Publication date2000

Genes integrated near the telomeres of budding yeast have a variegated pattern of gene repression that is mediated by the silent information regulatory proteins Sir2p, Sir3p, and Sir4p. Immunolocalization and fluorescence in situ hybridization (FISH) reveal 6–10 perinuclear foci in which silencing proteins and subtelomeric sequences colocalize, suggesting that these are sites of Sir-mediated repression. Telomeres lacking subtelomeric repeat elements and the silent mating locus, HML, also localize to the periphery of the nucleus. Conditions that disrupt telomere proximal repression disrupt the focal staining pattern of Sir proteins, but not necessarily the localization of telomeric DNA. To monitor the telomere-associated pools of heterochromatin-binding proteins (Sir and Rap1 proteins) during mitotic cell division, we have performed immunofluorescence and telomeric FISH on populations of yeast cells synchronously traversing the cell cycle. We observe a partial release of Rap1p from telomeres in late G2/M, although telomeres appear to stay clustered during G2-phase and throughout mitosis. A partial release of Sir3p and Sir4p during mitosis also occurs. This is not observed upon HU arrest, although other types of DNA damage cause a dramatic relocalization of Sir and Rap1 proteins. The observed cell cycle dynamics were confirmed by direct epifluorescence of a GFP–Rap1p fusion. Using live GFP fluorescence we show that the diffuse mitotic distribution of GFP–Rap1p is restored to the interphase pattern of foci in early G1-phase.

  • Cell nucleus
  • SIR proteins
  • Rap1
  • Cell cycle
  • Telomeres
Affiliation Not a UNIGE publication
Citation (ISO format)
LAROCHE, Thierry et al. The Dynamics of Yeast Telomeres and Silencing Proteins through the Cell Cycle. In: Journal of Structural Biology, 2000, vol. 129, n° 2-3, p. 159–174. doi: 10.1006/jsbi.2000.4240
Main files (1)
Article (Published version)
ISSN of the journal1047-8477

Technical informations

Creation11/22/2019 2:53:00 PM
First validation11/22/2019 2:53:00 PM
Update time03/15/2023 6:25:47 PM
Status update03/15/2023 6:25:46 PM
Last indexation10/19/2023 11:38:25 AM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack