Project description:These datasets contain the RNA sequences of three kinds of sample replicate groups obtained from our experiment: the wild type (WT), SZOE, and szAR. They were taken in the time interval of 0, 10, 30 and 60 minutes. With these RNA sequences, we are profiling the touch response in Bradypodium distachyon taken at different times.
Project description:Optimization hydrophobic tagging reaction time (30 min to 2h) and evaluation of the HUNTER protocol performance with different amounts (25 ug to 400 ug) of purified rat brain proteome as starting material.
Project description:Optimization hydrophobic tagging reagent (hexadecanal or undecanal), reaction time (30 min to 16h) and evaluation of the HUNTER protocol performance with different amounts (25 ug to 400 ug) of purified Arabidopsis thaliana Col-8 wt leaf proteome as starting material.
Project description:Comparison of protein termini in Arabidopsis thaliana vpe0 quadruple mutant and wildtype seedlings shortly after germination to identify differential processed proteins.
Project description:MYB plays a critical role as a regulator of erythropoieisis. We have shown that MYB silences epsilon and gamma-globin expression in erythroid progenitors. We here examine erythroid cells at the basophilic erythroblast stage of differentiation with MYB shRNA or control lentiviral transduction prior to differentiation. We have cultured CD34 cells and transduced the cells with lentiviruses harboring shRNAs targeting MYB or controls and then allowed the cells to differentiate down the erythroid lineage. At the basophilic erythroblast stage of differentiation, the cells were harvested and total RNA was extracted. This was used to hybridize to Affymetrix expression arrays using the HG-U133 Plus 2.0 platform to ascertain expression differences that occur with the knockdown of MYB.
Project description:De novo centromeres originate occasionally from non-centromeric regions of chromosomes, providing an excellent model system to study centromeric chromatin. The maize mini-chromosome Derivative 3-3 contains a de novo centromere, which was derived from a euchromatic site on the short arm of chromosome 9 that lacks traditional centromeric repeat sequences. Our previous study found that the CENH3 binding domain of this de novo centromere is only 288 kb with a high-density gene distribution with low-density of transposons. Here we applied next generation sequencing technology to analyze gene transcription, DNA methylation for this region. Our RNA-seq data revealed that active chromatin is not a barrier for de novo centromere formation. Bisulfite-ChIP-seq results indicate a slightly increased DNA methylation level after de novo centromere formation, reaching the level of a native centromere. These results provide insight into the mechanism of de novo centromere formation and subsequent consequences. RNA-seq was carried out using material from seedling and young leaves between control and Derivative 3-3. Bisulfite-ChIP-seq was carried out with anti-CENH3 antibodies using material from young leaves in Derivative 3-3.
Project description:Formaldehyde is a widely used fixative in biology and medicine. The current chemical model for formaldehyde cross-linking of proteins is the formation of a methylene bridge that incorporates one carbon atom into the link. Here, we present mass spectrometry data that largely refute this model. Instead, our data show that cross-linking of structured proteins mainly involves a reaction that incorporates two carbon atoms into the link. Under MS/MS fragmentation, the link cleaves symmetrically to yield unusual fragments with a modification of one carbon atom. We apply this new understanding of the underlying cross-linking chemistry to the structural approach of cross-linking coupled to mass spectrometry. First, we cross-linked a mixture of purified proteins with formaldehyde. Our new analysis readily identified tens of cross-links from these proteins, which fit well with their atomic structures. We then perform in-situ cross-linking of human cells in culture. We identified 469 intra-protein and 90 inter-protein cross-links, which also fit well with available atomic structures. Interestingly, many of these cross-links could not be mapped onto a known structure and thus provide new structural insights. We highlight an example in which formaldehyde cross-links localize the binding site of βNAC on the ribosome. We also find several interactions of actin with auxiliary proteins. Our findings not only expand our understanding of formaldehyde reactivity and toxicity, but also clearly demonstrate how to use this potent reagent for structural studies.
Project description:Cross-linking of living cells followed by mass spectrometry identification of cross-linked peptides (in situ CLMS) is an emerging technology to study protein structures in their native environment. One of the inherent difficulties of this approach is the high complexity of the samples following cell lysis. This difficulty largely limits the identification of cross-links to the more abundant proteins in the cell. Here, we describe a targeted approach in which an antibody pulls a specific protein-of-interest out of the lysate. Mass spectrometry analysis of the protein material that binds to the antibody can then identify considerably more cross-links on the antibody target and its interactors. By using an antibody against the CCT chaperonin, we obtained over two hundred cross-links that provide in situ evidence for the subunit arrangement of CCT and its main interactions with prefoldin. Antibodies against tubulin likewise provided in situ evidence for the structure of the microtubule including the seam. Finally, the approach was also successful in identifying cross-links on a protein expressing at very low amounts (tau in non-neuronal cells). These results demonstrate the general applicability of antibody-based sample simplification for in situ CLMS.
Project description:The intrinsically disordered protein, α-synuclein, implicated in synaptic vesicle homeostasis and neurotransmitter release, is also associated with several neurodegenerative diseases. The different roles of α-synuclein are characterized by distinct structural states (membrane-bound, dimer, tetramer, oligomer, and fibril), which are originated from its various monomeric conformations. The pathological states, determined by the ensemble of α-synuclein monomer conformations and dynamic pathways of interconversion between dominant states, remain elusive due to their transient nature. Here, we use inter-dye distance distributions from bulk time-resolved Förster resonance energy transfer as restraints in discrete molecular dynamics simulations to map the conformational space of the α-synuclein monomer. We further confirm the generated conformational ensemble in orthogonal experiments utilizing far-UV circular dichroism and cross-linking mass spectrometry. Single-molecule protein-induced fluorescence enhancement measurements show that within this conformational ensemble, some of the conformations of αsynuclein are surprisingly stable, exhibiting conformational transitions slower than milliseconds. Our comprehensive analysis of the conformational ensemble reveals essential structural properties and potential conformations that promote its various functions in membrane interaction or oligomer and fibril formation.