title: DNA replication factor C1 mediates genomic stability and transcriptional gene silencing in Arabidopsis.
abstract: Genetic screening identified a suppressor of ros1-1, a mutant of REPRESSOR OF SILENCING1 (ROS1; encoding a DNA demethylation protein). The suppressor is a mutation in the gene encoding the largest subunit of replication factor C (RFC1). This mutation of RFC1 reactivates the unlinked 35S-NPTII transgene, which is silenced in ros1 and also increases expression of the pericentromeric Athila retrotransposons named transcriptional silent information in a DNA methylation-independent manner. rfc1 is more sensitive than the wild type to the DNA-damaging agent methylmethane sulphonate and to the DNA inter- and intra- cross-linking agent cisplatin. The rfc1 mutant constitutively expresses the G2/M-specific cyclin CycB1;1 and other DNA repair-related genes. Treatment with DNA-damaging agents mimics the rfc1 mutation in releasing the silenced 35S-NPTII, suggesting that spontaneously induced genomic instability caused by the rfc1 mutation might partially contribute to the released transcriptional gene silencing (TGS). The frequency of somatic homologous recombination is significantly increased in the rfc1 mutant. Interestingly, ros1 mutants show increased telomere length, but rfc1 mutants show decreased telomere length and reduced expression of telomerase. Our results suggest that RFC1 helps mediate genomic stability and TGS in Arabidopsis thaliana.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Junguo
authors.initials: J
authors.lastname: Wang
authors.forename: Daisuke
authors.initials: D
authors.lastname: Miki
authors.forename: Ran
authors.initials: R
authors.lastname: Xia
authors.forename: Wenxiang
authors.initials: W
authors.lastname: Yu
authors.forename: Junna
authors.initials: J
authors.lastname: He
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Zheng
authors.forename: Jian-Kang
authors.initials: JK
authors.lastname: Zhu
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Gong
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D003001:Cloning, Molecular; D004249:DNA Damage; D019175:DNA Methylation; D020868:Gene Silencing; D018745:Genome, Plant; D009154:Mutation; D011995:Recombination, Genetic; D014158:Transcription, Genetic