Project description:A diversity of RNA molecule 5' ends are generated during transcriptional and post-transcriptional processes. Different RNA ends can confer or represent different functional activities and thus the identification of RNA end usage dynamics contributes to the functional characterization of RNA molecules. Here we present a method that enables the accurate identification of RNA 5' ends from samples with low amounts of total RNAs, and thus allow characterization of RNA regulatory mechanisms in specific cell-types.
Project description:MicroRNAs are important regulatory molecules in most eukaryotes and the identification of their mRNA targets is essential for their functional analysis. From inflorescence tissue of Arabidopsis, >28,000,000 signatures were sequenced from 5’ ends of polyadenylated products of mRNA decay. Within the set of ~27,000 transcripts included in the 3,500,000 non-redundant signatures, several previously predicted but non-validated miRNA targets were found. Like validated targets, most showed a single abundant signature at the miRNA cleavage site, particularly in libraries from a mutant deficient in the 5’ to 3’ exonuclease AtXRN4. Among the most unexpected miRNA targets discovered were miRNA precursor transcripts that are self-targeted by their own mature miRNA. Although the miRNAs of Arabidopsis have been extensively investigated, working in reverse from the cleaved targets, additional novel miRNAs were identified and validated. This deep and versatile approach will impact the study of other aspects of RNA processing beyond miRNA-target RNA pair analyses. Keywords: miRNA-target RNA pairs, Palallel analysis of RNA ends, PARE, SBS
Project description:Structure probing combined with next-generation sequencing (NGS) has provided novel insights into RNA structure-function relationships. To date such studies have focused largely on bacteria and eukaryotes, with little attention given to the third domain of life, archaea. Furthermore, functional RNAs have not been extensively studied in archaea, leaving open questions about RNA structure and function within this domain of life. With archaeal species being diverse and having many similarities to both bacteria and eukaryotes, the archaea domain has the potential to be an evolutionary bridge. In this study, we introduce a method for probing RNA structure in vivo in the archaea domain of life. We investigated the structure of ribosomal RNA (rRNA) from Methanosarcina acetivorans, a well-studied anaerobic archaeal species, grown with either methanol or acetate. After probing the RNA in vivo with dimethyl sulfate (DMS), Structure-seq2 libraries were generated, sequenced, and analyzed. We mapped the reactivity of DMS onto the secondary structure of the ribosome, which we determined independently with comparative analysis, and confirmed the accuracy of DMS probing in M. acetivorans. Accessibility of the rRNA to DMS in the two carbon sources was found to be quite similar, although some differences were found. Overall, this study establishes the Structure-seq2 pipeline in the archaea domain of life and informs about ribosomal structure within M. acetivorans.