ABSTRACT: we prepared synthetic proteins corresponding to 80 of the ribosome subunits by stable isotope labeling and then performed absolute quantification.
Project description:we prepared synthetic proteins corresponding to 30 of the proteasome subunits by stable isotope labeling and then performed absolute quantification.
Project description:MicroRNAs (miRNAs) have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous methods have been established to identify and quantify miRNAs. The shortness of miRNA sequence results in a high dynamic range of melting temperatures and, moreover, impedes a proper selection of detection probes or optimized PCR primers. While miRNA microarrays allow for massive parallel and accurate relative measurement of all known miRNAs, they have so far been less useful as an assay for absolute quantification. Here, we present a microarray based approach for global and absolute quantification of miRNAs. The method relies on an equimolar pool of about 1000 synthetic miRNAs of known concentration which is used as an universal reference and labeled and hybridized in a dual colour approach on the same array as the sample of interest. Each single miRNA is quantified with respect to the universal reference outbalancing bias related to sequence, labeling, hybridization or signal detection method. We demonstrate the accuracy of the method by various spike in experiments. Further, we quantified miRNA copy numbers in liver samples and CD34(+)CD133(-) hematopoietic stem cells. Total liver RNA was mixed with 2.5 fmol of each of 18 RNA oligonucleotides reverse complement to miRControl 3 probes and subsequently fluorescently labelled by 3â ligation. Total RNA mix was hybridized in a dual colour approach to microarrays versus a second labelled synthetic miRNA pool (n = 6). The synthetic miRNA pool consisted of 2.5 fmol of each of 891 non redundant miRNAs sequences and miRControl 3 sequences. The array data was normalized by calculating the median of the miRControl 3 present in the liver and UR sample. The miRNA amount was calculated with respect to the corresponding miRNA in the UR.
Project description:MicroRNAs (miRNAs) have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous methods have been established to identify and quantify miRNAs. The shortness of miRNA sequence results in a high dynamic range of melting temperatures and, moreover, impedes a proper selection of detection probes or optimized PCR primers. While miRNA microarrays allow for massive parallel and accurate relative measurement of all known miRNAs, they have so far been less useful as an assay for absolute quantification. Here, we present a microarray based approach for global and absolute quantification of miRNAs. The method relies on an equimolar pool of about 1000 synthetic miRNAs of known concentration which is used as an universal reference and labeled and hybridized in a dual colour approach on the same array as the sample of interest. Each single miRNA is quantified with respect to the universal reference outbalancing bias related to sequence, labeling, hybridization or signal detection method. We demonstrate the accuracy of the method by various spike in experiments. Further, we quantified miRNA copy numbers in liver samples and CD34(+)CD133(-) hematopoietic stem cells. The RNA extracted from 7 x 10^ 5 to 1 x 10^ 6 CD34(+)/CD133(-) cells of three different donors was analyzed. 1 µg of respective total RNA was mixed with 2.5 fmol of each of 18 RNA oligonucleotides reverse complement to miRControl 3 probes and subsequently fluorescently labelled by 3’ ligation. Total RNA mix was hybridized in a dual colour approach to microarrays versus a second labelled synthetic miRNA pool. The synthetic miRNA pool consisted of 2.5 fmol of each of 954 non redundant miRNAs sequences and miRControl 3 sequences. The array data was normalized by calculating the median of the miRControl 3 present in the CD34(+)/CD133(-) and UR sample. The miRNA amount was calculated with respect to the corresponding miRNA in the UR.
Project description:MicroRNAs (miRNAs) have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous methods have been established to identify and quantify miRNAs. The shortness of miRNA sequence results in a high dynamic range of melting temperatures and, moreover, impedes a proper selection of detection probes or optimized PCR primers. While miRNA microarrays allow for massive parallel and accurate relative measurement of all known miRNAs, they have so far been less useful as an assay for absolute quantification. Here, we present a microarray based approach for global and absolute quantification of miRNAs. The method relies on an equimolar pool of about 1000 synthetic miRNAs of known concentration which is used as an universal reference and labeled and hybridized in a dual colour approach on the same array as the sample of interest. Each single miRNA is quantified with respect to the universal reference outbalancing bias related to sequence, labeling, hybridization or signal detection method. We demonstrate the accuracy of the method by various spike in experiments. Further, we quantified miRNA copy numbers in liver samples and CD34(+)CD133(-) hematopoietic stem cells.
Project description:We developed a method to estimate the 3D interaction probabilities of chromatin loops across the genome on an absolute scale from Micro-C maps. To calibrate the method, we performed Micro-C on two engineered mouse embryonic stem cell (mESC) lines, each containing a fluorescently labeled chromatin loop that was quantified in previous live imaging studies. One loop is an endogenous loop containing the Fbn2 gene, and the other is a synthetic loop near the Npr3 gene. We performed two replicates of Micro-C per cell line. Using our absolute quantification method, we find that loops generally form with low probabilities. We also provide an ultra-deep merged Micro-C map for mESCs that combines all existing mESC Micro-C datasets to date, containing a total of 15.6 billion unique interactions.
Project description:A quantitative view of cellular functions requires precise measures of the rates of biomolecule production, especially proteins-the direct effectors of biological processes. Here we present a genome-wide approach, based on ribosome profiling, for measuring absolute protein synthesis rates. The resultant E. coli dataset transforms our understanding of the extent to which protein synthesis is precisely controlled to optimize function and efficiency. For example, members of multi-protein complexes are made in precise proportion to their stoichiometry, whereas components of functional modules are produced differentially according to their hierarchical role. Estimates of absolute protein abundance also reveal principles used to optimize design. These include how the level of different types of transcription factors is optimized for rapid response, and how a metabolic pathway (methionine biosynthesis) balances production cost with activity requirements. More broadly, our studies reveal how general principles, important both for understanding natural systems and for synthesizing new ones, emerge from global quantitative analyses of protein synthesis. 4 samples of E. coli ribosome profiling and mRNA-seq, including biological replicates
Project description:MicroRNAs (miRNAs) have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous methods have been established to identify and quantify miRNAs. The shortness of miRNA sequence results in a high dynamic range of melting temperatures and, moreover, impedes a proper selection of detection probes or optimized PCR primers. While miRNA microarrays allow for massive parallel and accurate relative measurement of all known miRNAs, they have so far been less useful as an assay for absolute quantification. Here, we present a microarray based approach for global and absolute quantification of miRNAs. The method relies on an equimolar pool of about 1000 synthetic miRNAs of known concentration which is used as an universal reference and labeled and hybridized in a dual colour approach on the same array as the sample of interest. Each single miRNA is quantified with respect to the universal reference outbalancing bias related to sequence, labeling, hybridization or signal detection method. We demonstrate the accuracy of the method by various spike in experiments. Further, we quantified miRNA copy numbers in liver samples and CD34(+)CD133(-) hematopoietic stem cells.
Project description:Absolute quantification of proteome is one of the most important tasks in proteomic research. The aim in this analysis is providing proof-of-principle of our originally developed strategy for absolute quantification of multiple proteins present at various concentrations in a cell, using stable isotope-labeled peptide concatenated standard (PCS). This study also provides insights into structures of regulation of metabolic pathway and into biological mechanisms for regulation of expressed protein abundance.