Intrachromosomal Homologous Recombination in plnta is Significantly Stimulated in CAF-1 Mutants of Arabidopsis thaliana

Abstract

Chromatin assembly factor 1 (CAF-1) is a three-subunit complex, consisting of FAS1, FAS2 and MSI1, in Arabidopsis thaliana, that interacts with histones H3 and H4 and targets them to DNA after replication and DNA repair synthesis. In contrast to human and budding yeast, little is known about relationship between CAF-1 and DNA repair systems in higher plants. In this study, we analyzed the γ-ray sensitivity and frequency of homologous recombination (HR) that is one of the DNA repair systems in Arabidopsis CAF-1 mutants (fas1 and fas2). In contrast to budding yeast, fas1 and fas2 mutants showed increased sensitivity to γ-ray irradiation compared to wild-type plants. Expression of the AtRAD51 gene, which plays a central role in HR, was increased in fas1 and fas2 mutants in the absence of DNA damage treatment. Recombination assay revealed that intrachromosomal HR in planta is 40-fold stimulated in fas1 and fas2 mutants.