Contributors: Callum P Rakhit, Barbara Ottolini, Carolyn Jones, James H Pringle, Jacqueline A Shaw, L. Miguel Martins
... To test whether the addition of a peptide nucleic acid (PNA) clamp, which binds WT KRAS at codon 12, can increase the efficacy of mutation detection for KRASG12D within a targeted NGS setting. We tested the effect of clamping the wild-type KRAS sequence in a reference standard (Tru-Q 7, 1.3% Tier from Horizon Diagnostics, Cambridge, UK) with a KRAS c.35G>A mutation (KRASG12D) at an allelic frequency (AF) of 1.3% assessed by digital droplet PCR (ddPCR). We then re-tested the PNA on circulating-free DNA from a patient harbouring a KRASG12D mutation (at an AF of 3.2%, determined by ddPCR). Multiple runs were conducted using 10, 5, 2.5 and 1ng of DNA input.
Contributors: Tapio Lönnberg, Valentine Svensson, Kylie R. James, Daniel Fernandez-Ruiz, Ismail Sebina, Ruddy Montandon, Megan S. F. Soon, Lily G. Fogg, Arya Sheela Nair, Urijah N. Liligeto
... Single-cell RNA sequencing (scRNA-seq) was used to study the various transcriptional states of individual CD4+ T cells during blood-stage Plasmodium chabaudi infection in mice. This is an experimental model of malaria in which CD4+ T cells are essential for controlling parasite numbers, and which is characterized by concurrent development of Th1 and Tfh cells. We have used Plasmodium-specific TCR transgenic CD4+ T cells to minimise the effects of TCR diversity on Th fate decisions. Activated antigen-specific cells were studied at days 0, 2, 3, 4 and 7. In addition, dendritic cells and monocytes were studied at days 0 and 3. Cell lysis, RT and cDNA preamplification was performed using Fluidigm C1 system.
CLIP-seq of Trypanosoma brucei cells in procyclic stages to investigate transcriptome wide mapping of MRB8170 and MRB4160
... iCLIP-seq experiment to asses the binding of mitochondrially targeted MRB8170 and MRB4160 involved in RNA editing on a genomic scale. Furthermore, to investigate what subsets of maxicircles transcripts (pan-edited, minimally-edited and never-edited) are bound to both the above proteins in vivo.
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Principles for RNA metabolism and alternative transcription initiation within closely spaced promoters
... Mammalian transcriptomes are complex and formed by extensive promoter activity. Moreover, gene promoters are largely divergent and initiate transcription of reverse-oriented promoter upstream transcripts (PROMPTs). Although PROMPTs are commonly terminated early, influenced by early polyadenylation (pA) sites, promoters often cluster so that the divergent activity of one might impact another. Here, we find that the distance between promoters strongly correlates with the expression, stability and length of their associated PROMPTs. Adjacent promoters driving divergent mRNA transcription support PROMPT formation, but due to pA site constraints, these transcripts tend to spread into the neighboring mRNA on the same strand. This mechanism to derive new alternative mRNA transcription start sites (TSSs) is also evident at closely spaced promoters supporting convergent mRNA transcription. We suggest that basic building blocks of divergently transcribed core promoter pairs, in combination with the wealth of TSSs in mammalian genomes, provides a framework with which evolution shapes transcriptomes. Mapping of paired 5’ and 3’ends of capped and polyadenylated RNAs from RRP40-depleted and eGFP control HeLa cells and using transcript isoform sequencing (TIF-Seq, see Pelechano et al. Nat Protoc 2014 (PMID: 24967623) and Pelechano et al. Nature 2013 (PMID: 23615609)).
Transcription profiling by array of Propionibacterium freudenreichii ssp. shermanii in cheese ripening in warm and cold conditions
... Propionibacterium freudenreichii is an important starter culture used in the manufacture of Swiss-type cheeses. We have generated the complete genome sequence of a Propionibacterium freudenreichii ssp. shermanii strain JS at the Institute of Biotechnology, University of Helsinki, by using a combination of pyrosequencing with GS FLX and GS FLX Titanium series reagents (Roche) and SOLiD 4 (Life Technologies), ABI 3130xl Genetic Analyzer (Life Technologies), and PacBio RS II (Pacific Biosciences) instruments. Initial genome annotation was carried out using RAST, and additional functional annotation information for each CDS was obtained from BLANNOTATOR, CDD, and KAAS. Accession number for genome sequence is PRJEB12148. This submission is for the transcriptome analysis of Propionibakcterium freudenreichii in cheese ripening under warm and cold conditions. The RNA reads were mapped to the reference genome PRJEB12148.
microRNA-Seq of Ras induced Epithelial to Mesenchymal Transition (EMT) in Madin-Darby Canine Kidney (MDCK) cells
Contributors: Priyank Shukla, Claus Vogl, Barbara Wallner, Doris Rigler, Mathias Müller and Sabine Macho-Maschler
... To gain more information on the expression of microRNAs during EMT induced by oncogenic Ras in MDCK cells, we performed deep sequencing (Illumina HiSeq2000) of MDCK and MDCK-Ras cells and compared their genome-wide microRNA expression profiles. RNA-Seq data from the same study has also been deposited at ArrayExpress under accession number E-MTAB-3301 (https://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-3301/).
... Transposable elements (TEs) have been active in the mammalian genome for hundreds of millions of years and each TE has had a distinct period of transpositional activity, followed by inactivation. Mice carrying reporter transgenes can be used to model transcriptional silencing at TEs. A mutagenesis screen for modifiers of epigenetic gene silencing produced a line with a null mutation in Trim33. Heterozygous mutants displayed increased expression of the reporter transgene. ChIP-seq of Trim33 in testis revealed 9,109 peaks, mostly at promoters, across the mouse genome. Trim33 was enriched at many RLTR10B elements that are among the youngest retrotransposons in the mouse genome. RNA-seq revealed that testis of mice haploinsufficient for Trim33 had altered expression of a small group of genes. The gene with the most significant increase, Nmnat3, was found to be transcribed from an upstream RLTR10B element. We show that Trim33 is involved in repressing RLTR10B elements in mouse testis. Examination of Trim33 binding using ChIP sequencing and the result of Trim33 haploinsufficiency using RNA sequencing, in mouse testis
Aldh1b1 controlled timing of pancreas specification is important for β cell functionality and glucose homeostasis in the adult
... Maintenance of normal glucose homeostasis is disturbed in diabetes. In the β cell, this involves a glucose sensor converting increased glucose levels to insulin secretion. Understanding the developmental regulatory networks that define a fully functional β cell is important for elucidating the genetic origins of the disease and deriving mature β cells for therapy. Here we show that Aldh1b1 regulates the timing of differentiation in the developing pancreas and the patterning of β cells. In its absence, expression of key β cell transcription factors is deregulated at birth. Null animals become glucose intolerant and hyperglycemic with age. Beta cell dysfunction is associated with extensive transcripteome changes, increased oxidative stress, energy depletion and defects in both glucose sensing and stimulus coupling secretion. These findings identify Aldh1b1 as a central regulator of the transition from the pancreas endocrine progenitor to the committed β cell and demonstrate that changes in the timing of this transition manifest much later in adult life with β cell dysfunction. Islets were isolated from postnatal day one and 8 week old Aldh1b1 null and wt mice. For each P1 samples islets from three mice were combined. Each week 8 sample came from a single mouse. Three samples were analysed per genotype and time point
... Total RNA was extracted from morpholigcally abnormal and wildtype sibling zebrafish biliary mutants initially identified in a chemical mutagenesis screen. The 3' ends of fragmented RNA were pulled down using polyT oligos attached to magnetic beads, reverse transcribed, made into Illumina libraries and sequenced using IlluminaHiSeq paired-end sequencing. Protocol: Total RNA was extracted and DNase treated. Fragmented RNA was enriched for the 3 ends by pull down using a polyT oligo attached to magnetic beads. An RNA oligo comprising part of the Illumina adapter 2 was ligated to the 5 end of the captured RNA and the RNA was eluted from the beads. Reverse transcription was primed with an anchored polyT oligo with part of Illumina adapter 1 at the 5 end followed by 12 random bases, then an 8 base indexing tag, then CG and 14 T bases. An Illumina library with full adapter sequence was produced by PCR. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
RNA-Seq profiling of single bovine oocyte transcript abundance and its modulation by cytoplasmic polyadenylation
Contributors: Reyes JM, Chitwood JL, Ross PJ
... Polyadenylated RNA from individual germinal vesicle and metaphase II ooyctes was amplified and processed for Illumina sequencing. Increases in polyadenylated transcript abundance were observed and are likely due to cytoplasmic polyadenylation. Transcriptomic analysis of GV and MII bovine oocytes.