TDP-1, the C. elegans ortholog of TDP-43, limits the accumulation of double stranded RNA

C. elegans mutants deleted for TDP-1, an ortholog of the neurodegeneration-associated RNA binding protein TDP-43, display only mild phenotypes. Nevertheless, transcriptome sequencing revealed that many RNAs were altered in accumulation and/or processing in the mutant. Analysis of these transcriptional abnormalities demonstrates that a primary function of TDP-1 is to limit formation or stability of double-stranded RNA. Specifically, we found that deletion of tdp-1: 1) preferentially alters the accumulation of RNAs with inherent double stranded structure (dsRNA); 2) increases the accumulation of nuclear dsRNA foci, 3) enhances the frequency of adenosine-to-inosine RNA editing, and 4) dramatically increases the amount of transcripts immunoprecipitable with a dsRNA-specific antibody, including intronic sequences, RNAs with antisense overlap to another transcript, and transposons. We also show that TDP-43 knockdown in human cells results in accumulation of dsRNA , indicating that suppression of dsRNA is a conserved function of TDP-43 in mammals. Altered accumulation of structured RNA may account for some of the previously described molecular phenotypes (e.g., altered splicing) resulting from reduction of TDP-43 function. 24 samples: 3 tdp-1 polyA samples with 3 N2 controls, 3 tdp1J2 immunoprecipitated samples and tdp1 total RNA input with 3 N2 J2 immunoprecipitated controls (with N2 input), 3 tdp1 total RNA samples for RNA editing analysis with 3 N2 total RNA controls and an adr-2 mutant control, 2 tdp1 CHIPseq samples with RNAsecontrol.