An ACF1-ISWI chromatin-remodeling complex is required for DNA replication through heterochromatin.
The mechanism by which the eukaryotic DNA-replication machinery penetrates condensed chromatin structures to replicate the underlying DNA is poorly understood. Here we provide evidence that an ACF1-ISWI chromatin-remodeling complex is required for replication through heterochromatin in mammalian cells. ACF1 (ATP-utilizing chromatin assembly and remodeling factor 1) and an ISWI isoform, SNF2H (sucrose nonfermenting-2 homolog), become specifically enriched in replicating pericentromeric heterochromatin. RNAi-mediated depletion of ACF1 specifically impairs the replication of pericentromeric heterochromatin. Accordingly, depletion of ACF1 causes a delay in cell-cycle progression through the late stages of S phase. In vivo depletion of SNF2H slows the progression of DNA replication throughout S phase, indicating a functional overlap with ACF1. Decondensing the heterochromatin with 5-aza-2-deoxycytidine reverses the effects of ACF1 and SNF2H depletion. Expression of an ACF1 mutant that cannot interact with SNF2H also interferes with replication of condensed chromatin. Our data suggest that an ACF1-SNF2H complex is part of a dedicated mechanism that enables DNA replication through highly condensed regions of chromatin.
Collins
Nadine
N
Marie Curie Research Institute, The Chart, Oxted, Surrey RH8 0TL, UK.
Poot
Raymond A
RA
Kukimoto
Iwao
I
García-Jiménez
Custodia
C
Dellaire
Graham
G
Varga-Weisz
Patrick D
PD
D016475:3T3 Cells; D000251:Adenosine Triphosphatases / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D016590:Aphidicolin / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002478:Cells, Cultured; D002503:Centromere / Q000276:immunology / Q000378:metabolism; D002843:Chromatin / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004261:DNA Replication; D015257:DNA-Cytosine Methylases / Q000378:metabolism; D000077209:Decitabine; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017353:Gene Deletion; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006570:Heterochromatin / Q000502:physiology*; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism; D011479:Protamines; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016196:S Phase; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014407:Tumor Cells, Cultured; D000092468:Bromodomain Containing Proteins
D000251:Adenosine Triphosphatases; D016590:Aphidicolin; D001374:Azacitidine; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004247:DNA; D015257:DNA-Cytosine Methylases; D000077209:Decitabine; D004791:Enzyme Inhibitors; D049452:Green Fluorescent Proteins; D006570:Heterochromatin; D008164:Luminescent Proteins; D009687:Nuclear Proteins; D011479:Protamines; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C492319:BAZ1A protein, human; D000092468:Bromodomain Containing Proteins; C086468:ISWI protein; C068621:protamine 2; C029641:DNA modification methylase HpaII; C409462:SMARCA5 protein, human; C498725:Smarca5 protein, mouse