AGO1 | Argonaute 1

PGs are RNA granules to which also PVA RNA can localize.(A) Fractions containing PGs labeled with P0YFP were isolated from PVACPmut infected leaf lysates (+ sample), as described in materials and methods. Lysates from non-infected leaves expressing P0YFP were fractionated similarly (- sample). Three parallel fractions of each sample type were used for fluorescence quantification and relative fluorescence units are given as a mean ± standard deviation. (B) Fractions quantified in (A) were imaged using epifluorescence microscopy to show successful capture of PVA-induced PGs. Scale bar; 500 ?m. (C) PG fractions were isolated from mock-infiltrated leaves (-) and PVACPmut RNA-expressing leaves (+) at 3 DAI and subjected to a western blot detection of endogenous HCpro, P0 and AGO1. The asterisks denote the expected position of the corresponding protein. (D) Similar samples enriched for PGs as in (A and B), were incubated with or without RNAse A and imaged using epifluorescence microscopy. Scale bar; 20 ?m. (E) RNAse A-mediated release of fluorescence from isolated PGs (D) was quantified by analyzing fluorescence in total, soluble and low-speed pellet fractions after RNAse A treatment compared to control samples (n = 3). (F) PG fractions were prepared from leaves expressing PVA together with either P0YFP (control) or Strep-III-tagged P0 (P0SIII), and subjected to Strep-tag based affinity purification. RNA was isolated from the affinity-purified samples and subjected to reverse transcription (RT+), followed by PCR detection of viral RNA. Total RNA from PVA infected leaves was used as a positive control for RT-PCR. The RT-minus control (RT-) was negative. (G) Bacteriophage ? B-box RNA elements were fused to the 3´ UTR within PVA?GDD icDNA (PVAB-box; S1 Fig). Binding of ?N22RFP to the B-box RNA element enabled visualization of PVAB-box RNA in vivo. PGs were induced either by PVA?GDD (control) or PVAB-box and visualized by P0YFP (green channel), and ?N22RFP was co-expressed to label B-box RNA. The RFP signal was mainly found in nuclei due to the nuclear localization signal present in ?N22RFP, but also in the cytoplasm and PGs in the presence of PVAB-box (magenta channel). The images are projections of Z-stacks with a single layer inset from the area indicated with an arrow. Scale bar; 10 ?m.

miRNAs and ta-siRNAs are recruited to membranes by AGO1.(A) Detection of three miRNAs in total extracts and the microsomal fraction in wild type (Col) and ago1-36. The ago1-36 mutant lacks the full-length AGO1 protein as shown by western blotting. HSC70 was a loading control. The three miRNAs were detected by northern blotting. 5S rRNA was an internal control and shown below each miRNA blot. The microsomal levels of the miRNAs were reduced in ago1-36. (B) A scatter plot showing comparable miRNA abundance in wild type (WT) and ago1-27 total extracts. Inset: box plots illustrating the distribution of miRNA RPMR values in WT and ago1-27. (C) A scatter plot showing that miRNAs have reduced microsomal enrichment in ago1-27 as compared with wild type. Microsomal enrichment was measured by M/T (ratio of levels in microsome vs. those in total extract). The degree of microsomal enrichment of miR390 (yellow dots) is largely unchanged, while that of most known ta-siRNA/phasiRNA triggers (red dots) is decreased in ago1-27. miR173’s (green dot) microsomal enrichment was weakly affected. (D) A scatter plot showing that 21-nt and 22-nt ta-siRNAs from TAS1-4 loci have reduced microsomal enrichment in ago1-27 as compared with wild type.DOI:http://dx.doi.org/10.7554/eLife.22750.010