Project description:The interactions between proteins and nucleic acids have a fundamental function in many biological processes well beyond nuclear gene transcription and include RNA homeostasis, protein translation and pathogen sensing for innate immunity. While our knowledge of the ensemble of proteins binding individual mRNAs in mammalian cells has greatly been augmented by recent surveys, no systematic study on the native proteins of human cells differentially engaging various types of nucleic acids in a non sequence-specific manner has been reported. We designed an experimental approach to cover the non sequence-specific RNA and DNA binding space broadly, including methylation, and test for its ability to interact with the human proteome. We used 25 rationally designed nucleic acid probes in an affinity purification mass spectrometry and bioinformatics workflow to identify proteins from whole cell extracts of three different human cell lines. The proteins were profiled for their binding preferences to the different general types of nucleic acids. The study identified 746 high confidence direct binders, 249 of which were devoid of previous experimental evidence for binding nucleic acids. We could assign 513 specific affinities for sub-types of nucleic acid probes to 219 distinct proteins and to individual domains. The evolutionary conserved protein YB-1, previously associated with cancer and gene regulation, is shown to bind methylated cytosine preferentially conferring YB-1 a potential epigenetic function. Collectively, the dataset represents a rich resource of experimentally determined nucleic acid-specific binding proteins in humans and, indirectly, for other species. Identification of genomic YB-1 binding sites in HEK293 cells
Project description:Coupling molecular biology to high throughput sequencing has revolutionized the study of biology. Molecular genomics techniques are continually refined to provide higher resolution mapping of nucleic acid interactions and nucleic acid structure. These assays are converging on single-nucleotide resolution measurements, but the sequence preferences of molecular biology enzymes can interfere with the accurate interpretation of the data. Enzymatic sequence preferences manifest more prominently as the resolution of these assays increase. We developed seqOutBias to seek out enzymatic sequence bias from experimental data and scale individual sequence reads to correct the bias. We show that this software efficiently and successfully corrects the sequence bias resulting from DNase-seq, TACh-seq, ATAC-seq, MNase-seq, and PRO-seq data.
Project description:The interactions between proteins and nucleic acids have a fundamental function in many biological processes well beyond nuclear gene transcription and include RNA homeostasis, protein translation and pathogen sensing for innate immunity. While our knowledge of the ensemble of proteins binding individual mRNAs in mammalian cells has greatly been augmented by recent surveys, no systematic study on the native proteins of human cells differentially engaging various types of nucleic acids in a non sequence-specific manner has been reported. We designed an experimental approach to cover the non sequence-specific RNA and DNA binding space broadly, including methylation, and test for its ability to interact with the human proteome. We used 25 rationally designed nucleic acid probes in an affinity purification mass spectrometry and bioinformatics workflow to identify proteins from whole cell extracts of three different human cell lines. The proteins were profiled for their binding preferences to the different general types of nucleic acids. The study identified 746 high confidence direct binders, 249 of which were devoid of previous experimental evidence for binding nucleic acids. We could assign 513 specific affinities for sub-types of nucleic acid probes to 219 distinct proteins and to individual domains. The evolutionary conserved protein YB-1, previously associated with cancer and gene regulation, is shown to bind methylated cytosine preferentially conferring YB-1 a potential epigenetic function. Collectively, the dataset represents a rich resource of experimentally determined nucleic acid-specific binding proteins in humans and, indirectly, for other species.
Project description:KH-type splicing regulatory protein (KHSRP) is a multifunctional nucleic acid binding protein. KHSRP regulates transcription, mRNA decay and translation, and miRNA biogenesis that influence distinct functions associated with cancer cell biology, such as inflammation and cell-fate determination. Our study uncovered novel mechanistic-based data on the tumor-promoting effects of KHSRP in colorectal cancer. We used microarrays to detail changes in gene expression upon specific knockdown of KHSRP in SW480 cells
Project description:BANC-seq (Binding Affinities to Native Chromatin by sequencing) allows determination of absolute apparent binding affinites of transcription factors to native chromatin in a genome-wide manner. In this study, we establish the method and show that chromatin and DNA sequence define binding affinites of FOXA1, SP1, YY1 and MYC/MAX complex. To relate the identified binding affinities to the actual transcriptional levels of these transcription factors in the cells used in this study, and to confirm that the nuclear isolation protocol used in the study does not lead to loss of nuclear proteins, we have generated whole proteomes including proteomics standards for absolute quantification of proteins. In addition, to validate some of the findings of the study, we have performed PAQMAN (Protein-nucleic acid affinity quantification by MAss spectrometry in nuclear extracts), as well as DNA pulldowns followed by mass spec.
Project description:To test whether the addition of a peptide nucleic acid (PNA) clamp, which binds WT KRAS at codon 12, can increase the efficacy of mutation detection for KRASG12D within a targeted NGS setting. We tested the effect of clamping the wild-type KRAS sequence in a reference standard (Tru-Q 7, 1.3% Tier from Horizon Diagnostics, Cambridge, UK) with a KRAS c.35G>A mutation (KRASG12D) at an allelic frequency (AF) of 1.3% assessed by digital droplet PCR (ddPCR). We then re-tested the PNA on circulating-free DNA from a patient harbouring a KRASG12D mutation (at an AF of 3.2%, determined by ddPCR). Multiple runs were conducted using 10, 5, 2.5 and 1ng of DNA input.
Project description:Nucleic Acid Sequencing for the study of division induced double strand breaks in the terminus region of Escherichia coli cells lacking RecBCD DNA repair enzymes.