Genome invasion by a hypomethylated satellite repeat in Australian crucifer Ballantinia antipoda

0509278 - ÚEB 2020 RIV GB eng J - Journal Article
Finke, A. - Mandáková, T. - Nawaz, Kashif - Vu, G.T.H. - Novák, Petr - Macas, Jiří - Lysák, M. A. - Pečinka, Aleš
Genome invasion by a hypomethylated satellite repeat in Australian crucifer Ballantinia antipoda.
Plant Journal. Roč. 99, č. 6 (2019), s. 1066-1079. ISSN 0960-7412. E-ISSN 1365-313X
R&D Projects: GA ČR GBP501/12/G090; GA MŠMT(CZ) LQ1601
Institutional support: RVO:61389030 ; RVO:60077344
Keywords : Brassicaceae * comparative genomics * DNA methylation * heterochromatin * satellite repeats
OECD category: Genetics and heredity (medical genetics to be 3); Genetics and heredity (medical genetics to be 3) (BC-A)
Impact factor: 6.141, year: 2019
Method of publishing: Open access
http://dx.doi.org/10.1111/tpj.14380

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 DNAs 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 (BaSAT1). BaSAT1 occupies about 10% of the B. antipoda nuclear genome in >250 000 copies. Unlike many other highly repetitive sequences, BaSAT1 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 BaSAT1 repeats were also devoid of heterochromatic histone H3K9me2 methylation. However, the factors decisive for the methylation status of BaSAT1 repeats remain currently unknown. In summary, we show that even highly repetitive sequences can exist as hypomethylated in the plant nuclear genome.
Permanent Link: http://hdl.handle.net/11104/0300032