Dataset Information

Genetic and epigenetic variation in 5S ribosomal RNA genes reveals genome dynamics in Arabidopsis thaliana.

ABSTRACT: Organized in tandem repeat arrays in most eukaryotes and transcribed by RNA polymerase III, expression of 5S rRNA genes is under epigenetic control. To unveil mechanisms of transcriptional regulation, we obtained here in depth sequence information on 5S rRNA genes from the Arabidopsis thaliana genome and identified differential enrichment in epigenetic marks between the three 5S rDNA loci situated on chromosomes 3, 4 and 5. We reveal the chromosome 5 locus as the major source of an atypical, long 5S rRNA transcript characteristic of an open chromatin structure. 5S rRNA genes from this locus translocated in the Landsberg erecta ecotype as shown by linkage mapping and chromosome-specific FISH analysis. These variations in 5S rDNA locus organization cause changes in the spatial arrangement of chromosomes in the nucleus. Furthermore, 5S rRNA gene arrangements are highly dynamic with alterations in chromosomal positions through translocations in certain mutants of the RNA-directed DNA methylation pathway and important copy number variations among ecotypes. Finally, variations in 5S rRNA gene sequence, chromatin organization and transcripts indicate differential usage of 5S rDNA loci in distinct ecotypes. We suggest that both the usage of existing and new 5S rDNA loci resulting from translocations may impact neighboring chromatin organization.

SUBMITTER: Simon L

PROVIDER: S-EPMC5887818 | biostudies-other | 2018 Apr

REPOSITORIES: biostudies-other

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Genetic and epigenetic variation in 5S ribosomal RNA genes reveals genome dynamics in Arabidopsis thaliana.

Simon Lauriane L Rabanal Fernando A FA Dubos Tristan T Oliver Cecilia C Lauber Damien D Poulet Axel A Vogt Alexander A Mandlbauer Ariane A Le Goff Samuel S Sommer Andreas A Duborjal Hervé H Tatout Christophe C Probst Aline V AV

Nucleic acids research 20180401 6

Organized in tandem repeat arrays in most eukaryotes and transcribed by RNA polymerase III, expression of 5S rRNA genes is under epigenetic control. To unveil mechanisms of transcriptional regulation, we obtained here in depth sequence information on 5S rRNA genes from the Arabidopsis thaliana genome and identified differential enrichment in epigenetic marks between the three 5S rDNA loci situated on chromosomes 3, 4 and 5. We reveal the chromosome 5 locus as the major source of an atypical, lon ...[more]

PMID: 29518237

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Project description:BACKGROUND: DNA methylation is an important biochemical mark that silences repetitive sequences, such as transposons, and reinforces epigenetic gene expression states. An important class of repetitive genes under epigenetic control in eukaryotic genomes encodes ribosomal RNA (rRNA) transcripts. The ribosomal genes coding for the 45S rRNA precursor of the three largest eukaryotic ribosomal RNAs (18S, 5.8S, and 25-28S) are found in nucleolus organizer regions (NORs), comprised of hundreds to thousands of repeats, only some of which are expressed in any given cell. An epigenetic switch, mediated by DNA methylation and histone modification, turns rRNA genes on and off. However, little is known about the mechanisms that specify and maintain the patterns of NOR DNA methylation. RESULTS: Here, we explored the extent of naturally-occurring variation in NOR DNA methylation among accessions of the flowering plant Arabidopsis thaliana. DNA methylation in coding regions of rRNA genes was positively correlated with copy number of 45S rRNA gene and DNA methylation in the intergenic spacer regions. We investigated the inheritance of NOR DNA methylation patterns in natural accessions with hypomethylated NORs in inter-strain crosses and defined three different categories of inheritance in F1 hybrids. In addition, subsequent analysis of F2 segregation for NOR DNA methylation patterns uncovered different patterns of inheritance. We also revealed that NOR DNA methylation in the Arabidopsis accession Bor-4 is influenced by the vim1-1 (variant in methylation 1-1) mutation, but the primary effect is specified by the NORs themselves. CONCLUSION: Our results indicate that the NORs themselves are the most significant determinants of natural variation in NOR DNA methylation. However, the inheritance of NOR DNA methylation suggests the operation of a diverse set of mechanisms, including inheritance of parental methylation patterns, reconfiguration of parental NOR DNA methylation, and the involvement of trans-acting modifiers.

Dataset Information

Genetic and epigenetic variation in 5S ribosomal RNA genes reveals genome dynamics in Arabidopsis thaliana.

Publications

Genetic and epigenetic variation in 5S ribosomal RNA genes reveals genome dynamics in Arabidopsis thaliana.

Similar Datasets

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