Biology subjects

Lee, D.-E.

Publications and source records attributed to Lee, D.-E..

2 recordsLinked to original sources

bioRxiv2025

Analysis of crosslinking sites suggests C. elegnas PIWI Argonaute exhibits flexible conformations for target recognition

Small RNAs play critical roles in gene regulation in diverse processes across organisms. Crosslinking, ligation, and analyses of sequence hybrid (CLASH) experiments have shown PIWI and Argonaute proteins bind to diverse mRNA targets, raising questions about their functional relevance and the degree of flexibility in target recognition. As crosslinking-induced mutations (CIMs) provides nucleotide-resolution of RNA binding sites, we developed MUTACLASH to systematically analyze CIMs in piRNA and miRNA CLASH data in C. elegans. We found CIMs are enriched at the nucleotide positions of mRNA corresponding to the center of targeting piRNAs and miRNAs. Notably, CIMs are also enriched at nucleotides with local pairing mismatches to piRNA. In addition, distinct patterns of CIMs are observed between canonical and non-canonical base pairing interactions, suggesting that the worm PIWI Argonaute PRG-1 adopts distinct conformations for canonical vs. non-canonical interactions. Critically, non-canonical miRNA or piRNA binding sites with CIMs exhibit more regulatory effects than those without CIMs, demonstrating CIM analysis as a valuable approach in assessing functional significance of small RNA targeting sites in CLASH data. Together, our analyses reveal the landscapes of Argonaute crosslinking sites on mRNAs and highlight MUTACLASH as an advanced tool in analyzing CLASH data.

molecular biology↗

bioRxiv2022

Transcriptome-wide analysis suggests piRNAs preferentially recognize the coding region of mRNAs in C. elegans

BackgroundPIWI-interacting RNAs (piRNAs) protect genome integrity by silencing transposon mRNAs and some endogenous mRNAs in various animals. However, C. elegans piRNAs fail to trigger gene silencing at many sequence-based predicted targeting sites. ResultsTo gain insights into the mechanisms that control piRNA silencing capability, we compared the transcriptome-wide predicted piRNA targeting sites to the in vivo piRNA binding sites. Surprisingly, while predicted piRNA targeting sites are enriched in 3 UTRs, we found that C. elegans piRNAs preferentially bind to coding regions (CDS) of target mRNAs, leading to preferential production of secondary silencing small RNAs in the CDS. Furthermore, our analyses suggest that Argonaute protein CSR-1 protects mRNAs from piRNA silencing through two distinct mechanisms - by inhibiting piRNA binding across the entire CSR-1 targeted transcript, and by inhibiting secondary silencing small RNA production locally at CSR-1 bound sites. However, CSR-1 is not responsible for the piRNA binding preference for the CDS. ConclusionsOur work identifies the CDS as the critical region that is uniquely competent for piRNA silencing in C. elegans. We speculate that the preference for CDS recognition by piRNAs may represent a mechanism to counteract the evolution of foreign protein-coding RNAs that evade piRNA surveillance.

genomics↗