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Genome invasion by a hypomethylated satellite repeat in Australian crucifer Ballantinia antipoda
Author(s) -
Finke Andreas,
Mandáková Terezie,
Nawaz Kashif,
Vu Giang T. H.,
Novák Petr,
Macas Jiri,
Lysak Martin A.,
Pecinka Ales
Publication year - 2019
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.14380
Subject(s) - heterochromatin , biology , genome , genetics , dna methylation , repeated sequence , epigenetics , interspersed repeat , satellite dna , genomic organization , human genome , gene , chromosome , gene expression
Summary Repetitive sequences are ubiquitous components of all eukaryotic genomes. They contribute to genome evolution and the regulation of gene transcription. However, the uncontrolled activity of repetitive sequences can negatively affect genome functions and stability. Therefore, repetitive DNA s are embedded in a highly repressive heterochromatic environment in plant cell nuclei. Here, we analyzed the sequence, composition and the epigenetic makeup of peculiar non‐pericentromeric heterochromatic segments in the genome of the Australian crucifer Ballantinia antipoda . By the 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 174 bp satellite repeat ( Ba SAT 1 ). Ba SAT 1 occupies about 10% of the B. antipoda nuclear genome in >250 000 copies. Unlike many other highly repetitive sequences, Ba SAT 1 repeats are hypomethylated; this contrasts with the normal patterns of DNA methylation in the B. antipoda genome. Detailed analysis of several copies revealed that these non‐methylated Ba SAT 1 repeats were also devoid of heterochromatic histone H3K9me2 methylation. However, the factors decisive for the methylation status of Ba SAT 1 repeats remain currently unknown. In summary, we show that even highly repetitive sequences can exist as hypomethylated in the plant nuclear genome.