Mitochondrial protein BmPAPI modulates the length of mature piRNAs.
PIWI proteins and their associated PIWI-interacting RNAs (piRNAs) protect genome integrity by silencing transposons in animal germlines. The molecular mechanisms and components responsible for piRNA biogenesis remain elusive. PIWI proteins contain conserved symmetrical dimethylarginines (sDMAs) that are specifically targeted by TUDOR domain-containing proteins. Here we report that the sDMAs of PIWI proteins play crucial roles in PIWI localization and piRNA biogenesis in Bombyx mori-derived BmN4 cells, which harbor fully functional piRNA biogenesis machinery. Moreover, RNAi screenings for Bombyx genes encoding TUDOR domain-containing proteins identified BmPAPI, a Bombyx homolog of Drosophila PAPI, as a factor modulating the length of mature piRNAs. BmPAPI specifically recognized sDMAs and interacted with PIWI proteins at the surface of the mitochondrial outer membrane. BmPAPI depletion resulted in 3'-terminal extensions of mature piRNAs without affecting the piRNA quantity. These results reveal the BmPAPI-involved piRNA precursor processing mechanism on mitochondrial outer membrane scaffolds.
['Honda|Shozo|S|', 'Kirino|Yoriko|Y|', 'Maragkakis|Manolis|M|', 'Alexiou|Panagiotis|P|', 'Ohtaki|Akashi|A|', 'Murali|Ramachandran|R|', 'Mourelatos|Zissimos|Z|', 'Kirino|Yohei|Y|']
D000818:Animals D001120:Arginine D060565:Argonaute Proteins D015152:Blotting, Northern D015153:Blotting, Western D012831:Bombyx D002352:Carrier Proteins D017931:DNA Primers D029721:Drosophila Proteins D004331:Drosophila melanogaster D005260:Female D005455:Fluorescent Antibody Technique D005854:Germ Cells D047468:Immunoprecipitation D026901:Membrane Transport Proteins D008928:Mitochondria D024101:Mitochondrial Proteins D010053:Ovary D017434:Protein Structure, Tertiary D012333:RNA, Messenger D034741:RNA, Small Interfering D034743:RNA-Induced Silencing Complex D060888:Real-Time Polymerase Chain Reaction D011994:Recombinant Proteins D020133:Reverse Transcriptase Polymerase Chain Reaction D020349:Surface Plasmon Resonance
BmPAPI piRNA PIWI TUDOR arginine methylation mitochondria