FAN, the homolog of mammalian Apoptosis Antagonizing Transcription Factor AATF/Che-1 protein, is involved in safeguarding genome stability through the ATR induced pathway in Arabidopsis

Cellular DNA can be damaged by endogenous or exogenous genotoxins. In plants, reduced genome stability can have a detrimental effect on development. Here, we show the identification of the fan mutant from an ethyl-methanesulfonate (EMS) mutagenized Arabidopsis Col-0 population on the basis of its short root and small leaf phenotype. The causative mutation was identified as a G-to-A transition at the border of the eighth intron and ninth exon of the At5G61330 gene, resulting in a mis-spliced mRNA transcript. FAN is a homolog of the mammalian AATF/Che-1 protein consisting of conserved AATF/Che-1 and TRAUB domains in Arabidopsis. In the fan mutant, under normal conditions, we detected DNA damage and cell death response at the root tip, while hypersensitivity to the exogenously applied hydroxyurea (HU) compared to Col-0, suggesting that FAN plays a role in the DNA damage response (DDR). Furthermore, our results showed that FAN is involved in DDR pathway regulated by ATM/RAD53-RELATED (ATR). Taken together, these suggest that FAN is required for meristem maintenance and the DNA damage response.