Evidence for silencing compartments within the yeast nucleus: a role for telomere proximity and Sir protein concentration in silencer-mediated repression
- Others:
- École normale supérieure - Lyon (ENS Lyon)
- Grenoble Institut des Neurosciences (GIN) ; Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Santé et de la Recherche Médicale (INSERM)
- Swiss Institute for Experimental Cancer Research - Lausanne (ISREC) ; Swiss Institute for Experimental Cancer Research
- Institut de Biologie François JACOB (JACOB) ; Direction de Recherche Fondamentale (CEA) (DRF (CEA)) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
- Institut de Recherche sur le Cancer et le Vieillissement (IRCAN) ; Université Nice Sophia Antipolis (1965 - 2019) (UNS) ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)
Description
Transcriptional repression at the silent mating-type loci in yeast requires the targeting of silent information regulator (Sir) proteins through specific interactions formed at cis-acting silencer elements. We show here that a reporter gene flanked by two functional silencers is not repressed when integrated at >200 kb from a telomere. Repression is restored by creation of a new telomere 13 kb from the integrated reporter or by elevated expression of SIRl, SIRS, and/or SIR4. Coupled expression represses in an additive manner, suggesting that all three factors are in limiting concentrations. When overexpressed, Sir3 and Sir4 are dispersed throughout the nucleoplasm, in contrast to wild-type cells where they are clustered in a limited number of foci together with telomeres. Efficient silencer function thus seems to require either proximity to a pool of concentrated Sir proteins, that is, proximity to telomeres, or delocalization of the silencing factors.
Abstract
International audience
Additional details
- URL
- https://hal.archives-ouvertes.fr/hal-02448182
- URN
- urn:oai:HAL:hal-02448182v1
- Origin repository
- UNICA