Transcription factor YY1 associates with pericentromeric gamma-satellite DNA in cycling but not in quiescent (G0) cells.
Pericentromeric gamma-satellite DNA is organized in constitutive heterochromatin structures. It comprises a 234 bp sequence repeated several thousands times surrounding the centromeric sequence of all murine chromosomes. Potential binding sites for transcription factor Yin Yang 1 (YY1), a repressor or activator of several cellular and viral genes, are present in pericentromeric gamma-satellite DNA. Using gel retardation and chromatin immunoprecipitation, we demonstrate in this work that YY1 specifically interacts in vitro and in vivo with gamma-satellite DNA. Using immunoFISH and confocal microscopy we show that YY1 specifically co-localizes with pericentromeric gamma-satellite DNA clusters organized in constitutive heterochromatin in murine L929 and 3T3 fibroblasts cell lines. Immunoelectron microscopy experiments further confirmed YY1 localization in heterochromatic areas. Overall, our results demonstrate for the first time that a fraction of YY1 is directly associated with constitutive heterochromatin structures. This association appears physiologically relevant since the association of YY1 with pericentromeric gamma-satellite DNA observed in cycling 3T3 fibroblasts strongly diminished in quiescent (G0) 3T3 fibroblasts. We discuss the implications of these results in the context of heterochromatin formation as well as with regard to the YY1-induced repression of euchromatic genes.
Régulation de la Transcription et Maladies Génétiques, CNRS UPR2228, IFR-95, Université René Descartes, 45 rue des Saints-Pères, 75270 Paris cedex 06, France.
Elena A
EA
Shestakova
Zeyni
Z
Mansuroglu
Houda
H
Mokrani
Nicolae
N
Ghinea
Eliette
E
Bonnefoy
D000818:Animals; D002453:Cell Cycle; D002455:Cell Division; D002467:Cell Nucleus / Q000737:chemistry; D002503:Centromere; D004276:DNA, Satellite / Q000032:analysis* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000032:analysis* / Q000378:metabolism; D050981:Erythroid-Specific DNA-Binding Factors; D022041:Euchromatin / Q000737:chemistry / Q000648:ultrastructure; D006570:Heterochromatin / Q000737:chemistry* / Q000648:ultrastructure; D051379:Mice; D008957:Models, Genetic; D041681:NIH 3T3 Cells; D016192:Resting Phase, Cell Cycle; D014157:Transcription Factors / Q000032:analysis* / Q000378:metabolism; D050986:YY1 Transcription Factor
D004276:DNA, Satellite; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D022041:Euchromatin; D006570:Heterochromatin; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494699:Yy1 protein, mouse