Project description:This dataset results from the discovery, characterization and validation of 74 genetically variant peptides from fingermark protein. These peptides contain single amino acid polymorphisms, the result of non-synonymous SNPs. Detection of these peptide markers in fingermark proteomic datasets allows inferences to be made about the genotype status of corresponding SNP alleles. These inferences provide an individual genetic profile that may be used to calculate random match probabilities and provide information about potential genetic background. Epidermal corneocytes from five European and four South Asian subjects were isolated, processed, proteolytically digested with trypsin and 0.75 µg applied to a Q ExactiveTM hybrid quadrupole-Orbitrap mass spectrometer. The resulting datasets were used for discovery of genetically variant peptides by a “bottom-up” analysis of potential variants identified in X!Tandem datasets (thegpm.org) or by a “top-down” proteomic confirmation of non-synonymous SNP variants shown to be present in corresponding subject exome datasets. The later method resulted in discovery of a rare allele that was not observed in the 1000 Genome Project. The cumulative profiles of detected genetically variant peptides were obtained for each subject. Candidate genetically variant peptides were then validated by comparing proteomically inferred SNP alleles with matching genotypes in exome datasets. An average of 28.8 ± 4.4 genetically variant peptides were detected from each subject. Across the 9 subjects a total of 264 SNP allele inferences were made resulting in 260 true positives and 4 false positives, a false positive rate of 1.5%. Random match probabilities were calculated using the genotype frequencies of common genetically variant peptides from the matching major populations in the 1000 genome project. Estimates ranged up to a value of 1 in 1.7 x 108, with a median probability of 1 in 2.4 x 106. When probabilities were recalculated using values from other major genetic population groups African values were considerably less conservative, with resulting likelihood ratios (AFR/other populations) ranging up to 6 orders of magnitude. Conversely there was no resolution among estimates obtained from all non-African population groups, where resulting random match probabilities were within an order of magnitude. These genetically variant peptides are a starting point for the development of targeted mass spectrometry-based proteomic analyses that will increase the sensitivity of peptide detection. This project represents a novel mode of genetic information that can be obtained from fingermarks and has the potential to complement or confirm other methods of human identification including analysis of ridge patterns or touch DNA.
Project description:DNA replication requires the faithful propagation of both genetic and epigenetic information. There is evidence that DNA polymerases play a role in transcriptional silencing, but the extent of their contribution and how it relates to heterochromatin maintenance is unclear. Analyzing a new hypomorphic pol2a mutant allele, we find that POL2A, the catalytic subunit of the DNA polymerase epsilon, maintains heterochromatin silencing and nuclear organization. We also found that POL2A inhibits DNA methylation. Using ChIP-seq in wild-type and pol2a mutants, we analyzed how this related to changes in heterochromatic histone modifications (H3K27me1, H3K27me3, H3K9me2) and H2A.W heterochromatic histone variant.
Project description:Our system recapitulates expected characteristics of the well characterized H3.3 histone variant, and show that we gain additional information by using a kinetic approach. Additionaly, our results on the less-studied MacroH2A2 variant revealed differential dynamic profiles of this M-bM-^@M-^\repressiveM-bM-^@M-^] histone variant. Our results represent a novel approach to histone dynamics in mammalian cells, reveal unanticipated dynamic behavior of the MacroH2A2 variant in pluripotent cells, and provide a resource for future studies of tissuespecific histone dynamics in vivo. We use a pulse-chase strategy for carrying out genome-wide measurements of histone dynamics to several histone variants in murine embryonic stem cells and somatic tissues. Genomic binding profiles of histone dynamics in normal ES cells, along with their differentiated counter parts, in MEFs, determined by ChIP-seq.
Project description:Our system recapitulates expected characteristics of the well characterized H3.3 histone variant, and show that we gain additional information by using a kinetic approach. Additionaly, our results on the less-studied MacroH2A2 variant revealed differential dynamic profiles of this “repressive” histone variant. Our results represent a novel approach to histone dynamics in mammalian cells, reveal unanticipated dynamic behavior of the MacroH2A2 variant in pluripotent cells, and provide a resource for future studies of tissuespecific histone dynamics in vivo.
Project description:Genetic variants in LZTR1 are associated with the development of Noonan syndrome. Here, we analyzed the proteome of cultured cardiomyocytes derived from hiPSCs with a pathological homozygous LZTR1 variant L580P in comparison to two wild type iPSC lines.
Project description:Bipolar disorder is a highly heritable mental illness, but the relevant genetic variants and molecular mechanisms are largely unknown. Recent GWASs have identified an intergenic region associated with both cognitive performance and bipolar disorder. This region contains dozens of putative fetal brain-specific enhancers and is located ~0.7 Mb upstream of the neuronal transcription factor POU3F2. We identified a candidate causal variant, rs77910749, that falls within a highly conserved putative enhancer, LC1. This human-specific variant is a single-base deletion in a PAX6 binding site and is predicted to be functional. We hypothesized that rs77910749 alters LC1 activity and hence POU3F2 expression during neurodevelopment. Indeed, transgenic reporter mice demonstrated LC1 activity in the developing cerebral cortex and amygdala. Furthermore, ex vivo reporter assays in embryonic mouse brain and human iPSC-derived cerebral organoids revealed increased enhancer activity conferred by the variant. To probe the in vivo function of LC1, we deleted the orthologous mouse region, which resulted in amygdala-specific changes in Pou3f2 expression. Lastly, ‘humanized’ rs77910749 knock-in mice displayed behavioral defects in sensory gating, an amygdala-dependent endophenotype seen in patients with bipolar disorder. Our study suggests a molecular mechanism underlying the long-speculated link between enhanced cognitive performance and neuropsychiatric disease.
Project description:Genetic variants in LZTR1 are associated with the development of Noonan syndrome. Here, we analyzed the proteome of cultured cardiomyocytes derived from hiPSCs with a pathological homozygous LZTR1 variant L580P in comparison to heterozygous and homozygous CRISPR/Cas9-corrected iPSC lines.
Project description:We have modeled the Fnip2 rs2291007 genetic variant in the mouse genome. In this study we aimed to investigate the effect of this genetic variant in the transcriptome of two metabolically relevant tissues: liver and white adipose tissue (WAT)
Project description:This dataset contains peptide array information from 120 patients from 5 different cancer types using classic blinded test/train method. This array is library 1 (GPL17600).