Measuring the influence of RNA binding proteins on A-to-I RNA editing in the Drosophila brain
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ABSTRACT: A-to-I RNA editing levels differ across tissues and cell types, but regulators of the editing process are largely unknown. We used RNA-seq on whole fly brains with different RNA binding proteins knocked down to test for A-to-I RNA editing level differences between controls and knockdowns.
Project description:We performed RNA-seq to profile gene expression in the heads and whole bodies of 32 isofemale fly lines from two divergent microclimates at 'Evolution Canyon' in Israel (16 fly lines from each microclimate). We also measured RNA editing levels in the head tissue of these flies.
Project description:The RNA editing enzyme ADAR chemically modifies adenosine (A) to inosine (I), which is interpreted by the ribosome as a guanosine. Here we assess cotranscriptional A-to-I editing in Drosophila, by isolating nascent RNA from adult fly heads and subjecting samples to high-throughput sequencing. There are a large number of edited sites within nascent exons. Nascent RNA from an ADAR null mutant strain was also sequenced, indicating that almost all A-to-I events require ADAR. Moreover, mRNA editing levels correlate with editing levels within the cognate nascent RNA sequence, indicating that the extent of editing is set cotranscriptionally. Surprisingly, the nascent data also identify an excess of intronic over exonic editing sites. These intronic sites occur preferentially within introns that are poorly spliced cotranscriptionally, suggesting a link between editing and splicing. We conclude that ADAR-mediated editing is more widespread than previously indicated and largely occurs cotranscriptionally. GSM914095: Fly genomic DNA sequencing. Sequenced on the Illumina GA II. GSM914102-GSM914113: Fly head nascent RNA profiles over 6 time points of a 12hr light:dark cycle in duplicate; sequenced on the Illumina GA II. GSM914114-GSM914119: Fly head nascent RNA profiles of yw, FM7, ADAR0 males in duplicate; sequenced on the HiSeq2000. GSM915213-GSM915214: Fly head mRNA profiles over 2 time points of a 12hr light:dark cycle; sequenced on the Illumina GA II. GSM915215-GSM915220: Fly head mRNA profiles over 6 time points of a 12hr light:dark cycle; paired-end sequenced on the Illumina GA II. GSM915221-GSM91526: Fly head mRNA profiles over 6 time points of a 12hr light:dark cycle; sequenced on the Illumina GA II.
Project description:We applied microfluidic multiplex PCR and deep sequencing (mmPCR-seq) to quantify RNA editing levels at targeted sites in 32 isofemale lines from two divergent microclimates at 'Evolution Canyon' in Israel (16 fly lines from each microclimate). Editing levels were compared between different populations at 25˚C , and were also compared between 25˚C and 18˚C within populations.
Project description:We report the application of mmPCR-seq to male whole body samples from 131 strains of the DGRP. We quantified RNA editing at 605 different loci using a microfluidic multiplex PCR method coupled with deep sequencing. RT-PCR amplification of 605 loci from 131 fly strains to quantify RNA editing levels.
Project description:Autism spectrum disorder (ASD) is a neurodevelopmental disease with complex heterogeneity and aberrations in multiple levels of neurobiology. Recently, our understanding of the molecular abnormalities in ASD has been greatly expanded through transcriptomic analyses of postmortem brains. However, a crucial molecular pathway involved in synaptic development, RNA editing, has not yet been studied on a genome-wide scale. Here we profiled the global patterns of adenosine-to-inosine (A-to-I) editing in a large cohort of ASD cortices and cerebella. Strikingly, we observed a global bias of hypoediting in ASD brains, common to different brain regions and involving many genes with critical neurological function. The large-scale RNA editing changes allowed us to reveal novel insights of RNA editing regulation. Through genome-wide protein-RNA binding analyses and detailed molecular assays, we show that the Fragile X proteins, FMRP and FXR1P, interact with ADAR protens and modulate A-to-I editing. Furthermore, we observed convergent patterns of RNA editing alterations between ASD and Fragile X syndrome, thus establishing RNA editing as a novel molecular link underlying these two highly related diseases. Our findings support a role for RNA editing dysregulation in ASD pathophysiology and highlight novel mechanisms for RNA editing regulation.
Project description:We used an improved INTACT (Isolation of Nuclei Tagged in A specific Cell Type) technique to isolate RNA from purified nuclei from different neuronal populations of the Drosophila brain. Using microfluidic multiplex PCR and sequencing (mmPCR-seq), we determined gene expression and A-to-I RNA editing levels at editing sites across nine distinct neuronal sub-populations and a pan-neuronal control.
Project description:Autism spectrum disorder (ASD) is a neurodevelopmental disease with complex heterogeneity and aberrations in multiple levels of neurobiology. Recently, our understanding of the molecular abnormalities in ASD has been greatly expanded through transcriptomic analyses of postmortem brains. However, a crucial molecular pathway involved in synaptic development, RNA editing, has not yet been studied on a genome-wide scale. Here we profiled the global patterns of adenosine-to-inosine (A-to-I) editing in a large cohort of ASD cortices and cerebella. Strikingly, we observed a global bias of hypoediting in ASD brains, common to different brain regions and involving many genes with critical neurological function. The large-scale RNA editing changes allowed us to reveal novel insights of RNA editing regulation. Through genome-wide protein-RNA binding analyses and detailed molecular assays, we show that the Fragile X proteins, FMRP and FXR1P, interact with ADAR protens and modulate A-to-I editing. Furthermore, we observed convergent patterns of RNA editing alterations between ASD and Fragile X syndrome, thus establishing RNA editing as a novel molecular link underlying these two highly related diseases. Our findings support a role for RNA editing dysregulation in ASD pathophysiology and highlight novel mechanisms for RNA editing regulation.
Project description:Autism spectrum disorder (ASD) is a neurodevelopmental disease with complex heterogeneity and aberrations in multiple levels of neurobiology. Recently, our understanding of the molecular abnormalities in ASD has been greatly expanded through transcriptomic analyses of postmortem brains. However, a crucial molecular pathway involved in synaptic development, RNA editing, has not yet been studied on a genome-wide scale. Here we profiled the global patterns of adenosine-to-inosine (A-to-I) editing in a large cohort of ASD cortices and cerebella. Strikingly, we observed a global bias of hypoediting in ASD brains, common to different brain regions and involving many genes with critical neurological function. The large-scale RNA editing changes allowed us to reveal novel insights of RNA editing regulation. Through genome-wide protein-RNA binding analyses and detailed molecular assays, we show that the Fragile X proteins, FMRP and FXR1P, interact with ADAR protens and modulate A-to-I editing. Furthermore, we observed convergent patterns of RNA editing alterations between ASD and Fragile X syndrome, thus establishing RNA editing as a novel molecular link underlying these two highly related diseases. Our findings support a role for RNA editing dysregulation in ASD pathophysiology and highlight novel mechanisms for RNA editing regulation.
Project description:The RNA editing enzyme ADAR chemically modifies adenosine (A) to inosine (I), which is interpreted by the ribosome as a guanosine. Here we assess cotranscriptional A-to-I editing in Drosophila, by isolating nascent RNA from adult fly heads and subjecting samples to high-throughput sequencing. There are a large number of edited sites within nascent exons. Nascent RNA from an ADAR null mutant strain was also sequenced, indicating that almost all A-to-I events require ADAR. Moreover, mRNA editing levels correlate with editing levels within the cognate nascent RNA sequence, indicating that the extent of editing is set cotranscriptionally. Surprisingly, the nascent data also identify an excess of intronic over exonic editing sites. These intronic sites occur preferentially within introns that are poorly spliced cotranscriptionally, suggesting a link between editing and splicing. We conclude that ADAR-mediated editing is more widespread than previously indicated and largely occurs cotranscriptionally.
Project description:We have shown previously that older flies are intrinsically more susceptible to Aβ42 toxicity. Building upon these findings, this study aimed to determine the mechanisms by which ageing increases this vulnerability to damage in the brain. A fixed dose of Aβ42 peptide was induced in young (5d) versus older (20d) fly neurons, and then gene and protein expression changes examined in dissected fly brains using microarray analyses. This unbiased approach has revealed genes and pathways that correlate with increased susceptibility of the ageing brain to proteotoxicity.