The euchromatic and heterochromatic landscapes are shaped by antagonizing effects of transcription on H2A.Z deposition.
A role for variant histone H2A.Z in gene expression is now well established but little is known about the mechanisms by which it operates. Using a combination of ChIP-chip, knockdown and expression profiling experiments, we show that upon gene induction, human H2A.Z associates with gene promoters and helps in recruiting the transcriptional machinery. Surprisingly, we also found that H2A.Z is randomly incorporated in the genome at low levels and that active transcription antagonizes this incorporation in transcribed regions. After cessation of transcription, random H2A.Z quickly reappears on genes, demonstrating that this incorporation utilizes an active mechanism. Within facultative heterochromatin, we observe a hyper accumulation of the variant histone, which might be due to the lack of transcription in these regions. These results show how chromatin structure and transcription can antagonize each other, therefore shaping chromatin and controlling gene expression.
Hardy
Sara
S
Institut de recherches cliniques de Montréal, Montréal, Québec, Canada.
Jacques
Pierre-Etienne
PE
Gévry
Nicolas
N
Forest
Audrey
A
Fortin
Marie-Eve
ME
Laflamme
Liette
L
Gaudreau
Luc
L
Robert
François
F
D045744:Cell Line, Tumor; D022041:Euchromatin; D006570:Heterochromatin; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism; D014158:Transcription, Genetic
D022041:Euchromatin; D006570:Heterochromatin; D006657:Histones; D012319:RNA Polymerase II