Search

The degradation of small RNAs in plants and animals is associated with small RNA 3′ truncation and 3′ uridylation and thus relies on exonucleases and nucleotidyl transferases. ARGONAUTE (AGO) proteins associate with small RNAs in vivo and are essential for not only the activities but also the stability of small RNAs. AGO1 is the microRNA (miRNA) effector in Arabidopsis, and its closest homolog, AGO10, maintains stem cell homeostasis in meristems by sequestration of miR165/6, a conserved miRNA acting through AGO1. Here, we show that SMALL RNA DEGRADING NUCLEASES (SDNs) initiate miRNA degradation by acting on AGO1-bound miRNAs to cause their 3′ truncation, and the truncated species are uridylated and degraded. We report that AGO10 reduces miR165/6 accumulation by enhancing its degradation by SDN1 and SDN2 in vivo. In vitro, AGO10-bound miR165/6 is more susceptible to SDN1-mediated 3′ truncation than AGO1-bound miR165/6. Thus, AGO10 promotes the degradation of miR165/6, which is contrary to the stabilizing effect of AGO1. Our work identifies a class of exonucleases responsible for miRNA 3′ truncation in vivo and uncovers a mechanism of specificity determination in miRNA turnover. This work, together with previous studies on AGO10, suggests that spatially regulated miRNA degradation underlies stem cell maintenance in plants. [ABSTRACT FROM AUTHOR]

In the Data Deposition section of the Material and Methods, there is an error in the seventh sentence. Reference 1 Yu Y, Ji L, Le BH, Zhai J, Chen J, Luscher E, et al. (2017) ARGONAUTE10 promotes the degradation of miR165/6 through the SDN1 and SDN2 exonucleases in I Arabidopsis i . [Extracted from the article]

Purpose: To investigate the values of gemstone spectral imaging (GSI)-dual-energy computed tomography (DECT) in differentiation of renal cell carcinoma (RCC) and minimal-fat renal angiomyolipoma (MF-RAML).Patients and Methods: Twenty-one patients with ischemic RCC and 19 patients with MF-RAML were enrolled in this study. GSI was performed on them, and the spectrum signs were analyzed.Results: I(H2O), H2O(I), I(fat), and fat(I) concentrations, normalized I concentration, and effective atomic number of corticomedullary phase and parenchymal phase in enhanced GSI-DECT in ischemic RCC group were all significantly lower than those in MF-RAML group (P < 0.05). CT value and absolute slope rate of spectral attenuation curve in two phases in ischemic RCC group were also significantly lower than those in MF-RAML group (P < 0.05).Conclusion: GSI-DECT has provided a new idea and method for differential diagnosis of ischemic RCC and MF-RAML, with high-clinical values. [ABSTRACT FROM AUTHOR]

The analytical validation is reported for a targeted methylation-based cell-free DNA multi-cancer early detection test designed to detect cancer and predict the cancer signal origin (tissue of origin). A machine-learning classifier was used to analyze the methylation patterns of >105 genomic targets covering >1 million methylation sites. Analytical sensitivity (limit of detection [95% probability]) was characterized with respect to tumor content by expected variant allele frequency and was determined to be 0.07%-0.17% across five tumor cases and 0.51% for the lymphoid neoplasm case. Test specificity was 99.3% (95% confidence interval, 98.6–99.7%). In the reproducibility and repeatability study, results were consistent in 31/34 (91.2%) pairs with cancer and 17/17 (100%) pairs without cancer; between runs, results were concordant for 129/133 (97.0%) cancer and 37/37 (100%) non-cancer sample pairs. Across 3- to 100-ng input levels of cell-free DNA, cancer was detected in 157/182 (86.3%) cancer samples but not in any of the 62 non-cancer samples. In input titration tests, cancer signal origin was correctly predicted in all tumor samples detected as cancer. No cross-contamination events were observed. No potential interferent (hemoglobin, bilirubin, triglycerides, genomic DNA) affected performance. The results of this analytical validation study support continued clinical development of a targeted methylation cell-free DNA multi-cancer early detection test. [ABSTRACT FROM AUTHOR]

Plant small RNAs are 3′ methylated by the methyltransferase HUA1 ENHANCER1 (HEN1). In plant hen1 mutants, 3′ modifications of small RNAs, including oligo-uridylation (tailing), are associated with accelerated degradation of microRNAs (miRNAs). By sequencing small RNAs of the wild type and hen1 mutants from Arabidopsis thaliana , rice (Oryza sativa), and maize (Zea mays), we found 3′ truncation prior to tailing is widespread in these mutants. Moreover, the patterns of miRNA truncation and tailing differ substantially among miRNA families but are conserved across species. The same patterns are also observable in wild-type libraries from a broad range of species, only at lower abundances. ARGONAUTE (AGO1), even with defective slicer activity, can bind these truncated and tailed variants of miRNAs. An ago1 mutation in hen1 suppressed such 3′ modifications, indicating that they occur while miRNAs are in association with AGO1, either during or after RNA-induced silencing complex assembly. Our results showed AGO1-bound miRNAs are actively 3′ truncated and tailed, possibly reflecting the activity of cofactors acting in conserved patterns in miRNA degradation. [ABSTRACT FROM AUTHOR]

Summary: Translation inhibition is a major but poorly understood mode of action of microRNAs (miRNAs) in plants and animals. In particular, the subcellular location where this process takes place is unknown. Here, we show that the translation inhibition, but not the mRNA cleavage activity, of Arabidopsis miRNAs requires ALTERED MERISTEM PROGRAM1 (AMP1). AMP1 encodes an integral membrane protein associated with endoplasmic reticulum (ER) and ARGONAUTE1, the miRNA effector and a peripheral ER membrane protein. Large differences in polysome association of miRNA target RNAs are found between wild-type and the amp1 mutant for membrane-bound, but not total, polysomes. This, together with AMP1-independent recruitment of miRNA target transcripts to membrane fractions, shows that miRNAs inhibit the translation of target RNAs on the ER. This study demonstrates that translation inhibition is an important activity of plant miRNAs, reveals the subcellular location of this activity, and uncovers a previously unknown function of the ER. PaperClip: Display Omitted [ABSTRACT FROM AUTHOR]

A quantitative proteomic analysis of the response to dry needling combined with static stretching treatment was performed in a rat model of active myofascial trigger points (MTrPs). 36 rats were divided into a model group (MG), a stretching group (SG) and a dry needling combined with stretching group (SDG). We performed three biological replicates to compare large-scale differential protein expression between groups by tandem mass tag (TMT) labeling technology based on nanoscale liquid chromatography mass spectrometry analysis (LC–MS/MS). Hierarchical clustering, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and protein-protein interaction network analyses were performed for the general characterization of overall enriched proteins. For validation of the results of TMT, the candidate proteins were verified by parallel reaction monitoring (PRM) analysis. 285 differentially expressed proteins between groups were identified and quantified. Tight junction pathway played a dominant role in dry needling combined with static stretching treatment for the rat model of active MTrPs. Three candidate proteins, namely actinin alpha 3, calsequestrin-1 and parvalbumin alpha, were further validated, consistent with the results of LC–MS/MS. This is the first proteomics-based study to report the therapeutic mechanism underlying dry needling and static stretching treatment for MTrPs. Further functional verification of the potential signaling pathways and the enriched proteins is warranted. [ABSTRACT FROM AUTHOR]