Ballantinia antipoda
Repetitive sequences are ubiquitous components of eukaryotic genomes, which contribute to the regulation of transcription and genome evolution. To prevent their uncontrolled and largely negative activity, they are embedded in the repressive heterochromatic environment rich in DNA methylation. Here, we analyzed the sequence composition and the epigenetic makeup of a peculiar non-pericentromeric DNA methylation-poor heterochromatic segments in the genome of the Australian crucifer Ballantinia antipoda. By combination of high throughput sequencing, graph-based clustering and cytogenetics, we found that the heterochromatic segments consist of a mixture of unique sequences and an A-T rich 177 bp satellite repeat (BaSAT1), which occupies about 10% of B. antipoda nuclear genome in >250,000 copies. Individual copies show a surprising variation in DNA methylation and repressive histone methylation, which appears to be genetically pre-determined. BaSAT1 repeats containing cytosines in the symmetric context (CG or CHG, where H is A, T or C) are fully methylated, while those having cytosines exclusively in the asymmetric (CHH) configuration are free of both DNA methylation and H3K9me2. This shows that the presence or the absence of repressive epigenetic marks is determined primarily genetically, and that the cytosines in symmetric sequence context are required for efficient and long-term DNA methylation of tandem repeats in plants.
ENA-FIRST-PUBLIC
2018-11-29T17:03:21Z
ENA-LAST-UPDATE
2018-09-12T18:02:46Z
External Id
SAMEA4895663
INSDC center name
MPIPZ COLOGNE
INSDC first public
2018-11-29T17:03:21Z
INSDC last update
2018-09-12T18:02:46Z
INSDC status
public
Submitter Id
DNASeq_250bp_PE_Bantipoda_run2
collection date
2008
estimated size
475 000 000
geographic location (country and/or sea)
Australia
geographic location (latitude)
-33.002
geographic location (longitude)
144.32
isolation and growth condition
long day
number of replicons
6
plant developmental stage
mature plant
plant growth medium
soil
plant structure
leaf
ploidy
mesoploid
sample name
DNASeq_250bp_PE_Bantipoda_run2
scientific_name
Ballantinia antipoda
source material identifiers
plant