Mouse Eosinophil Cationic Protein ELISA Kit

Double-stranded RNA (dsRNA)-specific endonucleases belonging to RNase III classes 3 and 2 process dsRNA precursors to small interfering RNA (siRNA) or microRNA, respectively, thereby initiating and amplifying RNA silencing-based antiviral defense and gene regulation in eukaryotic cells. However, we now provide evidence that a class I RNase III is involved in suppression of RNA silencing. The single-stranded RNA genome of sweet potato chlorotic stunt virus (SPCSV) encodes an RNase III (RNase3) homologous to putative class I RNase Ills of unknown function in rice and Arabidopsis. We show that RNase3 has dsRNA-specific endonuclease activity that enhances the RNA-silencing suppression activity of another protein (p22) encoded by SPCSV. RNase3 and p22 coexpression reduced siRNA accumulation more efficiently than p22 alone in Nicotiana benthamiana leaves expressing a strong silencing inducer (i.e., dsRNA). RNase3 did not cause intracellular silencing suppression or reduce accumulation of siRNA in the absence of p22 or enhance silencing suppression activity of a protein encoded by a heterologous virus. No other known RNA virus encodes an RNase III or uses two independent proteins cooperatively for RNA silencing suppression.

Previous studies showed that the biological activity and the eosinophil content of eosinophil cationic protein (ECP, RNase 3) are determined by single-nucleotide polymorphisms (SNPs) in the ECP (RNase3) gene. In this study, we report the prevalence of a common SNP in the eosinophil protein x/eosinophil-derived neurotoxin (EPX/EDN, RNase2) and the association with the cellular contents of EPX/EDN and ECP. The genes were sequenced and the EPX/EDN405(G>C) rs2013109 SNPs were also determined by TaqMan 5nuclease allelic discrimination assay. ECP and EPX/EDN in purified eosinophils or in whole blood extracts were analysed by sensitive immunoassays. The study included 379 non-allergic and allergic subjects. The genotype prevalence of the EPX/EDN405(G>C) polymorphism was GG 59%, GC 36% and CC 6%. The cellular contents of ECP and EPX/EDN were related in a reciprocal fashion with the sums of the protein contents being constant. The contents were associated with the ECP562(G>C) rs2233860 and EPX/EDN405(G>C) gene polymorphisms. The cellular content of eosinophil peroxidase (EPO) was not associated with the ECP and EPX/EDN genotypes. The prevalence of the EPX/EDN405(G>C) genotypes and the contents of the proteins were similar in non-allergic and allergic subjects. The production and storage of the two ancestral proteins, ECP and EPX/EDN likely share common regulatory mechanisms, which result in opposing productions of the two proteins.