A Tudor domain protein, SIMR-1, promotes siRNA production at piRNA-targeted mRNAs in < i > C. elegans < /i >

piRNAs play a critical role in the regulation of transposons and other germline genes. InCaenorhabditis elegans, regulation of piRNA target genes is mediated by themutator complex, which synthesizes high levels of siRNAs through the activity of an RNA-dependent RNA polymerase. However, the steps between mRNA recognition by the piRNA pathway and siRNA amplification by themutatorcomplex are unknown. Here, we identify the Tudor domain protein, SIMR-1, as acting downstream of piRNA production and upstream ofmutator complex-dependent siRNA biogenesis. Interestingly, SIMR-1 also localizes to distinct subcellular foci adjacent to P granules andMutator foci, two phase-separated condensates that are the sites of piRNA-dependent mRNA recognition and mutator complex-dependent siRNA amplification, respectively. Thus, our data suggests a role for multiple perinuclear condensates in organizing the piRNA pathway and promoting mRNA regulation by themutator complex.
Source: eLife - Category: Biomedical Science Tags: Chromosomes and Gene Expression Source Type: research