Mozgova, Iva
- Masaryk University
Abstract
Arabidopsis thaliana mutants dysfunctional in the evolutionarily conserved protein complex chromatin assembly factor-1 (CAF-1), which deposits the canonical histone H3 variant H3.1 during DNA synthesis-dependent chromatin assembly, display complex phenotypic changes including meristem and growth alterations, sensitivity to DNA-damaging agents, and reduced fertility. We reported previously that mutants in the FAS1 subunit of CAF-1 progressively lose telomere and 45S rDNA repeats. Here we show that multiple aspects of the fas phenotype are recovered immediately on expression of a reintroduced FAS1 allele, and are clearly independent of the recovery of rDNA copy-numbers and telomeres. In reverted lines, 45S rDNA genes are recovered to diverse levels with a strikingly different representation of their variants, and the typical association of nucleolar organizing region 4 with the nucleolus is perturbed. One of 45S rDNA variants (VAR1), which is silenced in wild-type (WT) plants without mutation history (Col-0 WT), dominates the expression pattern, whereas VAR2 is dominant in Col-0 WT plants. We propose an explanation for the variability of telomere and 45S rDNA repeats associated with CAF-1 function, suggesting that the differences in nuclear partitioning and expression of the rDNA variants in fas mutants and their revertants provide a useful experimental system to study genetic and epigenetic factors in gene dosage compensation.
Keywords
rDNA; telomeres; CAF-1; chromatin assembly; rRNA gene regulation; genome instability
Published in
Plant Journal
2016, volume: 88, number: 3, pages: 411-424
Publisher: WILEY-BLACKWELL
SLU Authors
UKÄ Subject classification
Botany
Genetics and Genomics
Publication identifier
- DOI: https://doi.org/10.1111/tpj.13257
Permanent link to this page (URI)
https://res.slu.se/id/publ/83313