Abstract
Most genes in Arabidopsis thaliana are members of gene families, which arose through large-scale segmental duplication of the genome or tandem duplication. Meanwhile, there are many insertions of recently discovered Helitron transposons that share high sequence similarity with one another; they constitute up to 2% of the genome. Homologous recombination between these homologous elements is thought to play a role in genome evolution. Here, we show that TEBICHI (TEB) protein, which contains putative DNA helicase and polymerase domains, functions cooperatively with the checkpoint kinase ATR in the repression of gene expression of duplicated genes, especially tandemly arrayed genes. In addition, based on analysis of morphological phenotypes, we found that genes adjacent to insertions of the Helitron transposon are also upregulated in teb or teb atr mutant. These results suggest that in teb mutants, defective DNA recombination during DNA replication leads to instability of chromatin structure and increased gene expression.
