Mouse centric and pericentric satellite repeats form distinct functional heterochromatin.
Heterochromatin is thought to play a critical role for centromeric function. However, the respective contributions of the distinct repetitive sequences found in these regions, such as minor and major satellites in the mouse, have remained largely unsolved. We show that these centric and pericentric repeats on the chromosomes have distinct heterochromatic characteristics in the nucleus. Major satellites from different chromosomes form clusters associated with heterochromatin protein 1alpha, whereas minor satellites are individual entities associated with centromeric proteins. Both regions contain methylated histone H3 (Me-K9 H3) but show different micrococcal nuclease sensitivities. A dinucleosome repeating unit is found specifically associated with major satellites. These domains replicate asynchronously, and chromatid cohesion is sustained for a longer time in major satellites compared with minor satellites. Such prolonged cohesion in major satellites is lost in the absence of Suv39h histone methyltransferases. Thus, we define functionally independent centromeric subdomains, which spatio-temporal isolation is proposed to be important for centromeric cohesion and dissociation during chromosome segregation.
Guenatri
Mounia
M
Institut Curie/Research section, UMR218 du Centre National pour la Recherche Scientifique, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
Bailly
Delphine
D
Maison
Christèle
C
Almouzni
Geneviève
G
D000818:Animals; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002503:Centromere / Q000648:ultrastructure*; D002843:Chromatin / Q000378:metabolism / Q000648:ultrastructure; D002875:Chromosomes / Q000648:ultrastructure; D004276:DNA, Satellite; D006570:Heterochromatin / Q000737:chemistry*; D006657:Histones / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase; D018386:Kinetochores / Q000648:ultrastructure; D008780:Methyltransferases / Q000235:genetics; D051379:Mice; D008836:Micrococcal Nuclease / Q000378:metabolism; D018895:Microsatellite Repeats; D005810:Multigene Family; D009154:Mutation; D041681:NIH 3T3 Cells; D010957:Plasmids / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000235:genetics; D016196:S Phase; D012854:Sister Chromatid Exchange; D013997:Time Factors
D002843:Chromatin; D004276:DNA, Satellite; D006570:Heterochromatin; D006657:Histones; D012097:Repressor Proteins; C498700:Suv39h1 protein, mouse; D008780:Methyltransferases; D008836:Micrococcal Nuclease; D001973:Bromodeoxyuridine