Project description:Transcriptome analysis in tobacco mutant plants using tomato Genechip Genome array Tobacco (Nicotiana tabacum cv. Petit Havanna) psaA and psbA deletion mutants were constructed through a targeted deletion of 767 and 1152 nucleotides of coding regions, respectively with two gene cassettes: psbAproR:uidA:psbterR and rrnR:aadA:rbcLterR coding for GUS reporter and spectinomycin selectable marker genes, respectively. Standard established procedures were followed for chloroplast transformation to generate the psaA and psbA deletion mutants based on the homologous recombination. Gene expression profiles in psaA and psbA tobacco mutant plants were analyzed using tomato Genechip Genome array to study the global changes in the expression of genome. Total RNA was isolated from psaA and psbA tobacco mutant plants along with the wild type plants. Biotin labeled cRNA was hybridized on tomato GeneChip Genome Array following the Affymetrix protocols. Two independent biological replicates were maintained.
Project description:Transcriptome analysis in tobacco mutant plants using tomato Genechip Genome array Tobacco (Nicotiana tabacum cv. Petit Havanna) psaA and psbA deletion mutants were constructed through a targeted deletion of 767 and 1152 nucleotides of coding regions, respectively with two gene cassettes: psbAproR:uidA:psbterR and rrnR:aadA:rbcLterR coding for GUS reporter and spectinomycin selectable marker genes, respectively. Standard established procedures were followed for chloroplast transformation to generate the psaA and psbA deletion mutants based on the homologous recombination. Gene expression profiles in psaA and psbA tobacco mutant plants were analyzed using tomato Genechip Genome array to study the global changes in the expression of genome.
Project description:we find METTL3 associates with polyribosomes and promotes translation. METTL3 depletion inhibits translation, and both wild-type and catalytically inactive METTL3 promote translation when tethered to the 3' untranslated region (UTR) of a reporter mRNA. Mechanistically, METTL3 enhances mRNA translation through an interaction with the translation initiation machinery. m6A seq in A549 and H1299 cells, RNA seq in METTL3 knockdown cells
Project description:we find METTL3 associates with polyribosomes and promotes translation. METTL3 depletion inhibits translation, and both wild-type and catalytically inactive METTL3 promote translation when tethered to the 3' untranslated region (UTR) of a reporter mRNA. Mechanistically, METTL3 enhances mRNA translation through an interaction with the translation initiation machinery.
Project description:We performed an experimental Cas13d-SARScov2 genome-wide screen to identify gRNAs that would allow Cas13d to degrade the viral RNA. We built mCherry reporter plasmids that express mCherry with a 3kb 3'UTR deriving from the SARScov2 genome. In total we designed 11 reporters covering the entire plus strand of the viral genome and 11 other reporters covering the entire minus strand. Each of the 22 mCherry reporter plasmids carries a U6 expression cassette containing a Cas13d gRNA that targets the 3'UTR of the mCherry reporter. Each reporter is represented by a pool of reporters each containing a different gRNA that targets mCherry 3'UTR for a total average of ~300 gRNA per 3'UTR. The entire pool of 22 reporters, each with a pool of ~300 different gRNAs constitutes a comprehensive set ~6,500 reporters (~ 6,500 different gRNAs) that allowed us to interrogate the entire SARScov2 plus and minus strand viral RNA for regions of vulnerability and targetability. In order to specifically interrogate Cas13d activity an remove the biases that would be introduced in the reporter expression by the presence of a large 3kb 3'UTR we used a case (presence of Cas13d) control (absence of Cas13d) design. Briefly, the ~6,500 reporters were lentiviral transduced in RKO cells, the cells were split in 2 populations, 1 population was transduced with Cas13d and the other serving as control did not. The population expressing Cas13d was FACS sorted in low mCherry (efficient gRNAs) and high mCherry (un-efficient gRNAs) in 2 biological replicates and the genomic DNA of these populations was extracted, gRNAs were PCR amplified and sequenced. For the population that did not express Cas13d, a low mCherry, one high mCherry and unsorted population were sequenced as control libraries.
Project description:mTOR regulates mRNA translation. Whereas ribosome-profiling suggested that mTOR exclusively stimulates translation of TOP (containing a 5â-terminal oligopyrimidine [5âTOP] motif) and TOP-like mRNAs, polysome-profiling implied that mTOR also modulates translation of non-TOP mRNAs. We show that ribosome-, but not polysome-profiling, is biased towards identification of TOP mRNAs as differentially translated while obscuring detection of changes in non-TOP mRNA translation. Transcription start site profiling by Nano-Cap Analysis of Gene Expression (nanoCAGE) revealed that many mTOR-sensitive mRNAs do not have 5âTOP motifs. Moreover, nanoCAGE showed that 5â UTR features distinguish two functionally and translationally distinct subsets of mTOR-sensitive mRNAs: i) those with short 5â UTRs enriched for mitochondrial functions such as respiration, that are translated in an eIF4E, but not eIF4A1-dependent manner and ii) mRNAs encoding proliferation- and survival-promoting proteins, that harbor long 5â UTRs, and require both eIF4E and eIF4A1 for their efficient translation. Selective inhibition of translation of mRNAs harboring long 5â UTRs via suppression of eIF4A leads to uncoupling of expression of proteins involved in respiration (e.g. ATP5O) from those protecting mitochondrial integrity (e.g. BCL-2) ultimately resulting in apoptosis. Conversely, simultaneous translational downregulation of both long and short 5â UTR mRNAs by mTOR inhibitors results in suppression of mitochondrial respiration and predominantly cytostatic effects. Therefore, 5â UTR features define differential modes of translation of functionally distinct mTOR-sensitive mRNAs, which explains discrepancies between the effects of mTOR and eIF4A inhibitors on neoplastic cells. Determination of 5'UTR lengths using nanoCAGE in MCF7 cells
Project description:The recycling of ribosomal subunits after translation termination is critical for efficient gene expression. Tma64 (eIF2D), Tma20 (MCT-1), and Tma22 (DENR) function as 40S recycling factors in vitro, but it is unknown whether they perform this function in vivo or serve as alternative initiation factors. Ribosome profiling of strains missing these factors revealed 80S ribosomes queued behind the stop codon, consistent with a block in 40S recycling. We found that unrecycled ribosomes could reinitiate translation at AUG codons in the 3’UTR, as evidenced by peaks in the footprint data and 3’UTR reporter analysis. In vitro translation experiments using reporter mRNAs containing upstream ORFs (uORFs) further established that reinitiation increased in the absence of these proteins. In some cases, 40S ribosomes appeared to rejoin with 60S subunits and undergo an alternative 80S reinitiation process in 3’UTRs. These results support a crucial role for Tma64, Tma20, and Tma22 in the recycling of 40S ribosomal subunits at stop codons and translation reinitiation.
Project description:Precise control of protein synthesis by engineering sequence elements in 5’ untranslated region (5’UTR) remains a fundamental challenge. To accelerate our understanding of cis-regulatory code embedded in 5’UTR, we devised massively parallel reporter assays from a synthetic mRNA library composed of over one million 5’UTR variants. A completely randomized 10-nucleotide sequence preceding an upstream open reading frame (uORF) and downstream GFP leads to a broad range of mRNA translatability and stability in mammalian cells. While efficient translation protects mRNA from degradation, uORF translation triggers mRNA decay in a UPF1-dependent manner. We also identified translational inhibitory elements in 5’UTR with G-quadruplex as a mark for mRNA decay in the P-body. Unexpectedly, an unstructured A-rich element in 5’UTR, while enabling cap-independent translation, destabilizes mRNAs in the absence of translation. Our results not only expose diverse sequence features of 5’UTR in controlling mRNA translatability, but also reveal ribosome-dependent and -independent mRNA surveillance pathways.
2020-06-01 | GSE145046 | GEO
Project description:Light regulated translation of psbA in plants