Project description:Deep sequencing of tRNAs have historically been nutoriously difficult. Here, we benchmark a newly developed library prep protocol termed OTTR agains intact tRNAs as well as tRNA fragments and show that OTTR outperforms any other commercial cloning protocol.
Project description:Here, we apply tRNA-seq and YAMAT-seq to profile the expressions of tRFs and tRNAs in plants. We provide a high-quality expression atlas of tRFs and tRNAs in Arabidopsis and rice, and uncover complex tRF population and the dynamic expressions of tRNA genes in plants.
Project description:We measured abundances of tRNAs by means of hydro-tRNA-seq (Gogakos et al., 2017), a method based on partial alkaline RNA hydrolysis that generates fragments suitable for sequencing, in the genome-reduced bacterium Mycoplasma pneumoniae.
Project description:The human genome encodes hundreds of tRNA genes but their individual contribution to the tRNA pool is not fully understood. Deep sequencing of tRNA transcripts (tRNA-Seq) can estimate tRNA abundance at single gene resolution, but tRNA structures and post-transcriptional modifications impair these analyses. Here we present a bioinformatics strategy to investigate differential tRNA gene expression and use it to compare tRNA-Seq datasets from cultured human cells and human brain. We find that sequencing caveats affect quantitation of only a subset of human tRNA genes. Unexpectedly, we detect several cases where the differences in tRNA expression among samples do not involve variations at the level of isoacceptor tRNA sets (tRNAs charged with the same amino acid but using different anticodons); but rather among tRNA genes within the same isodecoder set (tRNAs having the same anticodon sequence). Because isodecoder tRNAs are functionally equal in terms of genetic translation, their differential expression may be related to non-canonical tRNA functions. We show that several instances of differential tRNA gene expression result in changes in the abundance of tRNA-derived fragments (tRFs) but not of mature tRNAs. Examples of differentially expressed tRFs include: PIWI-associated RNAs, tRFs present in tissue samples but not in cells cultured in vitro, and somatic tissue-specific tRFs. Our data support that differential expression of tRNA genes regulate non-canonical tRNA functions performed by tRFs.
Project description:In this study, we use small RNA sequencing to investigate the effect of a null mutation of RNase 1 on the levels of tRNA halves and Y RNA fragments in the extracellular environment of cultured human cells. Complemented and extended by the use of northern blots, our results demonstrate that tRNAs and Y RNAs in the vesicle-depleted extracellular compartment are released from cells as full-length precursors. Following their release, tRNAs and Y RNAs are processed by RNase 1 into distinct fragments. In addition, our findings show that standard sequencing methods employed to detect tRNA fragments leave many of such fragments undetected and that a combination of end healing, 3’ deacylation and RNA modification removal before library preparation can substantially improve detection of tRNA halves and reduce biases.
Project description:tRNA related fragments(tRF) and tRNA halves(tiRNA) are novel class of short non-coding RNA derived from tRNAs. Using RNA sequencing, we evaluated the tRFs/tiRNAs expression profiles in relapsed/refractory multiple myeloma and multiple myeloma patients. Bioinformatics analyses indicated that tRFs/tiRNAs may be involved in the progression and drug-resistance of multiple myeloma.
Project description:The CCA-adding enzyme adds CCA to the 3' ends of transfer RNAs (tRNAs), a critical step in tRNA biogenesis that generates the amino acid attachment site. We found that the CCA-adding enzyme plays a key role in tRNA quality control by selectively marking unstable tRNAs and tRNA-like small RNAs for degradation. Instead of adding CCA to the 3' ends of these transcripts, CCA-adding enzymes from all three kingdoms of life add CCACCA. Here, we report deep sequencing analysis of the 3' ends of tRNA-Ser-CGA and tRNA-Ser-UGA from S. cerevisiae strains and show that hypomodified mature tRNAs are subjected to CCACCA (or poly(A) addition) as part of a rapid tRNA decay pathway in vivo. We conjecture that CCACCA addtion is a universal mechanism for controlling tRNA levels and preventing errors in translation. 121 samples analyzed in total, representing time courses of 10 different yeast strains; Biological replicates for each time point are included
Project description:Specific environmental insults cause the limited fragmentation of transfer RNAs (tRNAs) into tRNA-derived small RNAs (tsRNAs), which have been implicated in a wide range of biological processes. tRNA fragmentation results from endonucleolytic activities targeting single-stranded tRNA regions. However, how a tRNA with a single hydrolyzed phosphodiester bond in the anticodon loop (‘nicked’ tRNA) gives rise to distinct tsRNAs remains poorly understood. By utilizing biochemical fractionation of tsRNA-containing ribonucleoprotein complexes (RNPs) coupled with LC-MS/MS, we identified several RNA helicase enzymes that represent putative tRNA/tsRNA processing enzymes. Furthermore, a combination of biochemical and computational approaches revealed that specific RNA helicases indeed bind specific tRNAs with high affinity, as well as process nicked tRNAs into individual tsRNAs. In summary, these findings reveal that tRNA-derived duplexes can be substrates of well-known RNA helicases, thereby expanding their potential for cellular function to the creation of individual tsRNAs during the cellular stress response.