title: Transcription and histone modifications in the recombination-free region spanning a rice centromere.
abstract: Centromeres are sites of spindle attachment for chromosome segregation. During meiosis, recombination is absent at centromeres and surrounding regions. To understand the molecular basis for recombination suppression, we have comprehensively annotated the 3.5-Mb region that spans a fully sequenced rice centromere. Although transcriptional analysis showed that the 750-kb CENH3-containing core is relatively deficient in genes, the recombination-free region differs little in gene density from flanking regions that recombine. Likewise, the density of transposable elements is similar between the recombination-free region and flanking regions. We also measured levels of histone H4 acetylation and histone H3 methylation at 176 genes within the 3.5-Mb span. Active genes showed enrichment of H4 acetylation and H3K4 dimethylation as expected, including genes within the core. Our inability to detect sequence or histone modification features that distinguish recombination-free regions from flanking regions that recombine suggest that recombination suppression is an epigenetic feature of centromeres maintained by the assembly of CENH3-containing nucleosomes within the core. CENH3-containing centrochromatin does not appear to be distinguished by a unique combination of H3 and H4 modifications. Rather, the varied distribution of histone modifications might reflect the composition and abundance of sequence elements that inhabit centromeric DNA.
authors.affiliation: Department of Horticulture, University of Wisconsin, Madison, 53706, USA.
authors.forename: Huihuang
authors.initials: H
authors.lastname: Yan
authors.forename: Weiwei
authors.initials: W
authors.lastname: Jin
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Nagaki
authors.forename: Shulan
authors.initials: S
authors.lastname: Tian
authors.forename: Shu
authors.initials: S
authors.lastname: Ouyang
authors.forename: C Robin
authors.initials: CR
authors.lastname: Buell
authors.forename: Paul B
authors.initials: PB
authors.lastname: Talbert
authors.forename: Steven
authors.initials: S
authors.lastname: Henikoff
authors.forename: Jiming
authors.initials: J
authors.lastname: Jiang
mesh_terms: D002503:Centromere; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D006657:Histones / Q000378:metabolism*; D012275:Oryza / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D018744:DNA, Plant; D006657:Histones; D010940:Plant Proteins