D4Z4 as a prototype of CTCF and lamins-dependent insulator in human cells

Alexandre Ottaviani (1) , Caroline Schluth-Bolard (1) , Eric Gilson (1, 2, 3) , Frédérique Magdinier (1, 4)

1 LBMC - Laboratoire de Biologie Moléculaire de la Cellule
2 Department of Medical Genetics
3 Laboratoire de biologie et pathologie des génomes
4 GMGF - Génétique Médicale et Génomique Fonctionnelle

Using cellular models that mimic the organization of the subtelomeric 4q35 locus found in patients affected with Facio-Scapulo-Humeral Dystrophy (FSHD) and in healthy individuals, we recently investigated the biological function of the D4Z4 macrosatellite within this domain. We demonstrated that D4Z4 acts as a CTCF and A-type Lamins dependent insulator element exhibiting both enhancer-blocking and barrier activities, and displaces a telomere towards the nuclear periphery. This peripheral positioning activity lies within a short sequence that interacts with CTCF and A-type Lamins. Depletion in either of these two proteins suppresses these perinuclear activities, revealing the existence of a subtelomeric sequence that is sufficient to position an adjacent telomere to the nuclear periphery. We discuss here the biological implications of these results in the light of our current knowledge in related fields and the potential implication of other CTCF and A- type lamins insulators in the light of human pathologies.

Mots clés: CTCF; A-type lamins; D4Z4; FSHD; nuclear organization; insulator; position effect variegation; telomere; subtelomere

Domaines: Biologie cellulaire

Alexandre Ottaviani, Caroline Schluth-Bolard, Eric Gilson, Frédérique Magdinier. D4Z4 as a prototype of CTCF and lamins-dependent insulator in human cells. Nucleus, 2010, 1 (1), pp.30-36. ⟨ensl-00817391⟩