Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

ADAR2 reproducibly changes abundance and sequence of mature microRNAs in the mouse brain

ABSTRACT: This SuperSeries is composed of the SubSeries listed below. Refer to individual Series

ORGANISM(S): Mus musculus

SUBMITTER: Fritz Sedlazeck

PROVIDER: E-GEOD-61068 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

ADAR2 induces reproducible changes in sequence and abundance of mature microRNAs in the mouse brain.

Vesely Cornelia C Tauber Stefanie S Sedlazeck Fritz J FJ Tajaddod Mansoureh M von Haeseler Arndt A Jantsch Michael F MF

Nucleic acids research 20140926 19

Adenosine deaminases that act on RNA (ADARs) deaminate adenosines to inosines in double-stranded RNAs including miRNA precursors. A to I editing is widespread and required for normal life. By comparing deep sequencing data of brain miRNAs from wild-type and ADAR2 deficient mouse strains, we detect editing sites and altered miRNA processing at high sensitivity. We detect 48 novel editing events in miRNAs. Some editing events reach frequencies of up to 80%. About half of all editing events depend ...[more]

PMID: 25260591

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Project description:Background: Adenosine deaminases that act on RNA (ADARs) bind to double-stranded and structured RNAs and deaminate adenosines to inosines. This A to I editing is widespread and required for normal life and development. Besides mRNAs and repetitive elements, ADARs can target miRNA precursors. Editing of miRNA precursors can affect processing efficiency and alter target specificity. Interestingly, ADARs can also influence miRNA abundance independent of RNA-editing. In mouse embryos where editing levels are low, ADAR2 was found to be the major ADAR protein that affects miRNA abundance. Here we extend our analysis to adult mouse brains where high editing levels are observed. Results: Using Illumina deep sequencing we compare the abundances of mature miRNAs and editing events within them, between wild-type and ADAR2 knockout mice in the adult mouse brain. Reproducible changes in abundance of specific miRNAs are observed in ADAR2 deficient mice. Most of these quantitative changes seem unrelated to A to I editing events. However, many A to G transitions in cDNAs prepared from mature miRNA sequences, reflecting A to I editing events in the RNA, are observed with frequencies reaching up to 80%. About half of these editing events are primarily caused by ADAR2 while a few miRNAs show increased editing in the absence of ADAR2, suggesting preferential editing by ADAR1. Moreover, novel, previously unknown editing events were identified in several miRNAs. In general 64% of all editing events are located within the seed region of mature miRNAs. In one of these cases retargeting of the edited miRNA could be verified in reporter assays. Also, altered processing efficiency upon editing near a processing site could be experimentally verified. Conclusions: ADAR2 can significantly influence the abundance of certain miRNAs in the brain. Only in a few cases changes in miRNA abundance can be explained by miRNA editing. Thus, ADAR2 binding to miRNA precursors, without editing them, may influence their processing and thereby abundance. ADAR1 and ADAR2 have both overlapping and distinct specificities for editing of miRNA editing sites. Over 60% of editing occurs in the seed region possibly changing target specificities for many edited miRNAs. Examination of the effect of ADAR2 on mature miRNA abundance and sequence in adult mouse brain.

Project description:In this study, a whole-genome CombiMatrix Custom oligonucleotide tiling microarray with 90000 probes covering six sequenced Helicobacter pylori(H. pylori) genomes was designed and utilized for comparative genomic profiling of eight unsequenced strains isolated from patients with different gastroduodenal diseases in Heilongjiang province of China. Since significant genomic variation were found among these strains, an additional 76 H. pylori stains with different clinical outcomes isolated from various provinces of China were further tested by PCR to demonstrate this distinction. We observed several highly variable regions among strains of gastritis, gastric ulceration and gastric cancer. They are involved in genes associated with bacterial type I, type II and type III R-M system as well as in a virB gene neighboring the well studied cag pathogenic island. Previous studies have reported the diverse genetic characterization of this pathogenic island, but it is conserved in the strains tested by microarray in this study. Moreover, a number of genes involved in the type IV secretion system related to DNA horizontal transfer between H. pylori strains were identified based on the comparative analysis of the strain specific genes. These findings may provide new insights for discovering biomarkers for prediction of gastric diseases. Here we describe the design and use of a high-density oligonucleotide microarray covering six sequenced H. pylori genomes as well as several sequenced plasmids. The performance of this microarray is evaluated, and its utility is illustrated for the hybridization of genomic DNA in order to compare eight uncharacterized H. pylori strains which have not been sequenced with the six known, sequenced strains. We utilize this microarray to identify variable genomic region among H. pylori strains isolated from patients with different gastroduodenal diseases in a Chinese patient population. H. pylori isolates from 2 patients with chronic superficial gastritis, 2 patients with atrophic gastritis, 2 patients with gastric ulcer, and 2 patients with gastric cancer were studied. All eight strains were isolated from Heilongjiang province of China. A number of variable regions with high genetic diversity was identified. 26 selected genes were validated by large scale PCR in both microarray tested strains while an additional 76 strains were isolated from eight provinces.

Dataset Information

ADAR2 reproducibly changes abundance and sequence of mature microRNAs in the mouse brain

Publications

ADAR2 induces reproducible changes in sequence and abundance of mature microRNAs in the mouse brain.

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