Project description:It has been shown that in mammalian cells alternative transcription initiation is extensively regulated during development and across cell-types, which confers dynamic transcript 5âUTR repertoire. However it is underexplored how the heterogeneity of 5âUTR isoforms would affect the downstream steps for protein expression, such as translation. To this end, we globally compared the translational profile of distinct mRNA TSS isoforms in mouse fibroblast cells, by combining deep-sequencing based mRNA 5âends profiling and polysome fractionation. We demonstrated the extensive translation regulation conferred by TSS heterogeneity. 5'end sequencing in seven polysome fractions, in two replicates, using Illumina Hiseq2000
Project description:mRNA m5C, which has recently been implicated in the regulation of mRNA mobility, metabolism, and translation, plays important regulatory roles in various biological events. Two types of m5C sites are found in mRNAs. Type I m5C sites, which contain a 3’G-rich triplet motif and locate in the 5’ end of hairpin structures, are methylated by NSUN2. Type II m5C sites contain a 3’UCCA motif and locate in the loops of hairpin structures. However, their biogenesis remains unknown. Here we identified a novel mRNA methyltransferase that targets Type II m5C sites and generated BS-seq and RNA-seq data to verify our findings.
Project description:It has been shown that in mammalian cells alternative transcription initiation is extensively regulated during development and across cell-types, which confers dynamic transcript 5’UTR repertoire. However it is underexplored how the heterogeneity of 5’UTR isoforms would affect the downstream steps for protein expression, such as translation. To this end, we globally compared the translational profile of distinct mRNA TSS isoforms in mouse fibroblast cells, by combining deep-sequencing based mRNA 5’ends profiling and polysome fractionation. We demonstrated the extensive translation regulation conferred by TSS heterogeneity.
Project description:We followed the polysomal association of maternal and early zygotic transcriptome over the first few hours of embryonic development, prior to and after MBT. We isolated polysome-associated (bound) and non-polysome-associated (unbound) mRNAs using sucrose gradient centrifugation followed by size fractionation. Using next generation sequencing (RNA-seq), we profiled the transcriptome in polysome-bound and unbound fractions. Our analysis revealed distinct dynamics of polysome association of cytoplasmically polyadenylated maternal mRNAs.
Project description:To obtain translational profiles for all mRNAs, polysome preparations are separated according to their size using a sucrose gradient and the mRNAs in each fraction are identified and quantified with DNA microarrays. Starting with exponentially growing cells, we analyzed 12 polysome fractions using DNA microarrays containing elements for all known and predicted genes of fission yeast. This approach provided data on average numbers of associated ribosomes for most transcripts.
Project description:Gene expression in the total RNA and heavy polysome fractions of Eif4g3 siRNA treated lymph node stromal cells (LNSCs) compared to control-sIRNA treated samples The objective of this study was to identify genes whose translation are reduced after silencing Eif4g3 (the gene which encodes the translation initiation factor eIF4GII). Genes with reduced translation are expected to have lower expression in RNA samples isolated from heavy polysomes but not in RNA samples isolated from whole cell lysates. LNSCs were grown in 10 cm plates, allowed to reach M-bM-^IM-% 80% confluency and then transfected with 400 pmol of control or Eif4g3 siRNA using Lipofectamine 2000. 7 plates were transfected with control or Eif4g3 siRNA. Total RNA was extracted from cells 48h after transfection. To isolate RNA from the heavy polysome fractions, cells were pooled, lysed and fractionated on a 10% to 60% continuous sucrose gradient. Fractions containing the heavy polysome fractions were pooled. RNA was extracted from these samples and used for microarrays on the Agilent Whole Mouse Genome Microarray Kit, 4M-CM-^W44K 2-color arrays.