Project description:A sequencing-based profiling method (RiboMeth-seq) for ribose methylations was used to study methylation patterns in mouse adult tissues and during development. In contrast to previous reports based on studies of human cancer cell lines, almost all methylation sites were close to fully methylated in adult tissues. A subset of sites was differentially modified in developing tissues compared to their adult counterparts and showed clear developmental dynamics. This provides the first evidence for ribosome heterogeneity at the level of rRNA modifications during mouse development. In a prominent example, the expression levels of SNORD78 during development appeared to be regulated by alternative splicing of the Gas5 host-gene and to correlate with the methylation level of its target site at LSU-G4593. The results are discussed in the context of the specialized ribosome hypothesis.
Project description:Sequencing-based profiling of ribose methylations is a new approach that allows for experiments adrressing dynamic changes on a large scale. Here, we apply such a method to spliceosomal snRNAs present in human whole cell RNA. Analysis of solid tissue samples confirmed all previously known sites and demonstrated close to full methylation at almost all sites. Methylation changes were revealed in biological experimental settings, using T cell activation as an example, and in the T cell leukemia model, Jurkat cells. Such changes could impact the dynamics of snRNA interactions during the spliceosome cycle and affect mRNA splicing efficiency and splicing patterns.
Project description:The major information-carrying macromolecules in the cell, DNA, RNA, and protein, carry an additional layer of information on top of their sequence in the form of modifications of residues. The modifications provide additional functional groups and impact the structure and function of the molecules. Cellular RNA molecules contain more than 100 different modifications and are found in all domains of life and in all major classes of RNA in eukaryotic organisms. Together these modifications constitute the epitranscriptome of which two-thirds are methylations with 2’-O methylation of the ribose moiety of the nucleotide as the most abundant. Many aspects of ribose methylation are underexplored because the existing methods for their detection are laborious and can only address a few modification sites at a time. Here, we introduce RiboMeth-Seq, a high-throughput sequencing based method and applies it to yeast ribosomal RNA. We detect all of the known as well as one new methylation site and provide evidence for hypomethylation at specific residues. Furthermore we demonstrate that many methylation events are interdependent and outline the timing of modifications during ribosome biogenesis. Our results demonstrate a novel and efficient approach to understanding of the role of modifications in ribosomal RNA folding and ribosome function. Recent evidence point to changes in ribose methylation patterns in cancer ribosomes and we anticipate that RiboMeth-Seq can be applied here as well as to other diseases in which ribosomes are affected, including the heritable ribosomopathies. Yeast RNA was degraded at denaturing conditions into small fragments, long enough to be mapped by sequence alignment to the reference genome (20-40 nucleotides). The fragments were ligated to RNA oligos using a tRNA ligase that was mutated to remove its kinase activity, reverse transcribed and the cDNA used as input for Ion semiconductor sequencing. The first and last nucleotides of the inserts were recorded using the full sequence for mapping and the read-ends plotted against the sequence. 2'-O-Methylated RNA positions are protected from cleavage, and read ends from such positions are therefore underrepresented compared to the surrounding positions.
Project description:The major information-carrying macromolecules in the cell, DNA, RNA, and protein, carry an additional layer of information on top of their sequence in the form of modifications of residues. The modifications provide additional functional groups and impact the structure and function of the molecules. Cellular RNA molecules contain more than 100 different modifications and are found in all domains of life and in all major classes of RNA in eukaryotic organisms. Together these modifications constitute the epitranscriptome of which two-thirds are methylations with 2’-O methylation of the ribose moiety of the nucleotide as the most abundant. Many aspects of ribose methylation are underexplored because the existing methods for their detection are laborious and can only address a few modification sites at a time. Here, we introduce RiboMeth-Seq, a high-throughput sequencing based method and applies it to yeast ribosomal RNA. We detect all of the known as well as one new methylation site and provide evidence for hypomethylation at specific residues. Furthermore we demonstrate that many methylation events are interdependent and outline the timing of modifications during ribosome biogenesis. Our results demonstrate a novel and efficient approach to understanding of the role of modifications in ribosomal RNA folding and ribosome function. Recent evidence point to changes in ribose methylation patterns in cancer ribosomes and we anticipate that RiboMeth-Seq can be applied here as well as to other diseases in which ribosomes are affected, including the heritable ribosomopathies.
Project description:A sequencing-based profiling method (RiboMeth-seq) for ribose methylations was used to study methylation patterns during Zebrafish (Danio rerio) development
Project description:Purpose: Examining the transcriptome of Bacteroides thetaiotaomicron VPI-5482 grown on ribose to look at global changes in regulation in vitro on the defined monosaccharide, ribose as a sole carbon source. Methods: Bacteroides thetaiotaomicron was grown on 5 mg/ml ribose or glucose as a sole carbon source in vitro. Fold change was calculated as ribose over glucose with n=3 biological replicates. Once cells reached an optical density corresponding to mid-log phase growth (absorbance between 0.6-0.8), RNA was isolated and rRNA depleted. Samples were multiplexed for sequencing on the Illumina HiSeq platform at the University of Michigan Sequencing Core. Data was analyzed using Arraystar software (DNASTAR, Inc.) using RPKM normalization with default parameters. Genes with significant up- or down-regulation were determined by the following criteria: genes with an average fold-change >5-fold and with at least 2/3 biological replicates with a normalized expression level >1% of the overall average RPKM expression level in either glucose or ribose, and a p-value < 0.05 (t test with Benjamini-Hochberg correction) Results: We identified 81 genes differentially expressed at a 5-fold cutoff when grown in ribose over the reference glucose condition, many of which are involved in other metabolic processes important for seemingly unrealted nutrients.
Project description:Ribosomal RNAs (rRNAs) are main effectors of mRNA decoding, peptide-bond formation and ribosome dynamics during translation. Ribose 2'-O-methylation is the most abundant rRNA chemical modification, and display a complex pattern in rRNA. We globally challenged rRNA 2'-O-Me by inhibiting the rRNA methyl-transferase fibrillarin (FBL) in human cells. Since FBL participates in rRNA processing, we wonder if FBL knockdown could alter the assembly of ribosomes.