IDN2 Interacts with RPA and Facilitates DNA Double-Strand Break Repair by Homologous Recombination in Arabidopsis.

Repair of DNA double-strand breaks (DSBs) is critical for the maintenance of genome integrity. We previously showed that DSB-induced small RNAs (diRNAs) facilitate homologous recombination-mediated DSB repair in Arabidopsis thaliana Here, we show that INVOLVED IN DE NOVO2 (IDN2), a double-stranded RNA binding protein involved in small RNA-directed DNA methylation, is required for DSB repair in Arabidopsis. We find that IDN2 interacts with the heterotrimeric replication protein A (RPA) complex. Depletion of IDN2 or the diRNA binding ARGONAUTE2 leads to increased accumulation of RPA at DSB sites and mislocalization of the recombination factor RAD51. These findings support a model in which IDN2 interacts with RPA and facilitates the release of RPA from single-stranded DNA tails and subsequent recruitment of RAD51 at DSB sites to promote DSB repair.

Global profiling of RNA-chromatin interactions reveals co-regulatory gene expression networks in Arabidopsis.

It is increasingly evident that various RNAs can bind chromatin to regulate gene expression and genome organization. Here we adapted a sequencing-based technique to profile RNA-chromatin interactions at a genome-wide scale in Arabidopsis seedlings. We identified more than 10,000 RNA-chromatin interactions mediated by protein-coding RNAs and non-coding RNAs. Cis and intra-chromosomal interactions are mainly mediated by protein-coding RNAs, whereas inter-chromosomal interactions are primarily mediated by non-coding RNAs. Many RNA-chromatin interactions tend to positively correlate with DNA-DNA interactions, suggesting their mutual influence and reinforcement. We further show that some RNA-chromatin interactions undergo alterations in response to biotic and abiotic stresses and that altered RNA-chromatin interactions form co-regulatory networks. Our study provides a global view on RNA-chromatin interactions in Arabidopsis and a rich resource for future investigations of regulatory roles of RNAs in gene expression and genome organization.

Replication of association of nine susceptibility loci with Graves' disease in the Chinese Han population.

This study is to evaluate the association of 9 single nucleotide polymorphisms (SNPs) with Graves' disease (GD) in different homogenous samples of the Chinese Han population. A total of 2,865 unrelated individuals were enrolled from Linyi City, Shandong Province, China, including 1,139 patients of GD and 1,726 controls. All 9 SNPs showed significant associations with GD (P < 1.3×10(-4), Bonferroni corrected Pc < 0.001). The most significant association was detected at rs2281388 at the HLA-DPB1 locus (P=1.3×10(-21); OR=1.62, 95% CI: 1.47-1.79). After adjusting for gender and age, 7 SNPs remained significantly associated with GD (P < 3.4×10(-4), Pc < 0.003). The risk of GD caused by any of these SNPs was not significantly different between female and male participants (Phet > 0.15). Four SNPs located in MHC regions were significantly associated with GD in different ages (P < 8.4×10(-4), Pc < 0.04). The risks of any SNP leading to the development of GD did not differ significantly in different ages (P_trend > 0.02, Pc > 0.18). The rs6457617 at the HLA-DR-DQ locus was significantly correlated with gender in GD patients (P=0.004, Pc =0.04). No significant correlation was found between any SNP and age of diagnosis in GD patients (P > 0.02, Pc > 0.17). The 9 previously identified SNPs are associated with GD in the Chinese Han population. And, gender and age may not influence the associations between the 9 SNPs and GD.