The histone chaperones ASF1 and HIRA are required for telomere length and 45S rDNA copy number homeostasis.

Genome stability is significantly influenced by the precise coordination of chromatin complexes that facilitate the loading and eviction of histones from chromatin during replication, transcription, and DNA repair processes. In this study, we investigate the role of the Arabidopsis H3 histone chaperones ANTI-SILENCING FUNCTION 1 (ASF1) and HISTONE REGULATOR A (HIRA) in the maintenance of telomeres and 45S rDNA loci, genomic sites that are particularly susceptible to changes in the chromatin structure. We find that both ASF1 and HIRA are essential for telomere length regulation, as telomeres are significantly shorter in asf1a1b and hira mutants.

KU70 and CAF-1 in Arabidopsis: Divergent roles in rDNA stability and telomere homeostasis.

Deficiency in chromatin assembly factor-1 (CAF-1) in plants through dysfunction of its components, FASCIATA1 and 2 (FAS1, FAS2), leads to the specific and progressive loss of rDNA and telomere repeats in plants. This loss is attributed to defective repair mechanisms for the increased DNA breaks encountered during replication, a consequence of impaired replication-dependent chromatin assembly. In this study, we explore the role of KU70 in these processes.