Project description:Stable expression of tRNA-Glu(UUC) and tRNA-Arg(CCG) followed by whole-genome transcript stability measurements using a-amanitin mediated inhibition of RNA Pol II.
Project description:Experiment comparing Low-density, CCg derived, progenitors (LDP) with high-density progenitors (HDP), and neurons (LDN) and astrocytes (LDA) derived from the LDP condition Keywords: other
Project description:Treatment of rice roots with glutamate (Glu) induces systemic disease resistance against rice blast in leaves. To analyze the effect of Glu on the transcriptome of rice, rice roots were treated with Glu solution, and then fourth leaves were harvested and analyzed by Agilent rice microarray.
Project description:Treatment of rice roots with glutamate (Glu) induces systemic disease resistance against rice blast in leaves. To analyze the effect of Glu on the transcriptome of rice, rice roots were treated with Glu solution, and then fourth leaves were harvested and analyzed by Agilent rice microarray. Rice plants were treated with Glu (10 mM) or mock (water) solution and leaves were analyzed at 9 and 24 h in two biological replicates.
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:Using a combination of ultraviolet circular dichroism, temperature-jump transient-infrared spectroscopy, and molecular dynamics simulations, we investigate the effect of salt bridges between different types of charged amino-acid residue pairs on ?-helix folding. We determine the stability and the folding and unfolding rates of 12 alanine-based ?-helical peptides, each of which has a nearly identical composition containing three pairs of positively and negatively charged residues (either Glu(-)/Arg(+), Asp(-)/Arg(+), or Glu(-)/Lys(+)). Within each set of peptides, the distance and order of the oppositely charged residues in the peptide sequence differ, such that they have different capabilities of forming salt bridges. Our results indicate that stabilizing salt bridges (in which the interacting residues are spaced and ordered such that they favor helix formation) speed up ?-helix formation by up to 50% and slow down the unfolding of the ?-helix, whereas salt bridges with an unfavorable geometry have the opposite effect. Comparing the peptides with different types of charge pairs, we observe that salt bridges between side chains of Glu(-) and Arg(+) are most favorable for the speed of folding, probably because of the larger conformational space of the salt-bridging Glu(-)/Arg(+) rotamer pairs compared to Asp(-)/Arg(+) and Glu(-)/Lys(+). We speculate that the observed impact of salt bridges on the folding kinetics might explain why some proteins contain salt bridges that do not stabilize the final, folded conformation.