The Application of Innovative High-Throughput Techniques to Serum Biomarker Discovery

Time-of-flight mass spectrometry continues to evolve as a promising technique for serum protein expression profiling and biomarker discovery. As seen in our initial SELDI-TOF MS and MALDI-TOF MS profiling study of serum for the assessment of breast cancer risk, many profiling strategies typically employ single chemical affinity beads or surfaces to decrease sample complexity of dynamic fluids like serum. However, most proteins, captured on a particular surface or bead, are not resolved in the lower mass range where mass spectrometers are most effective. To this end we have designed an expression profiling workflow that utilizes immobilized trypsin paramagnetic beads in order to reduce large mass proteins into peptides that are in the ideal mass range for serum expression profiling as well as for direct LIFT-MS/MS sequence determinations. We demonstrate that this bead-based trypsinization is efficient in digesting large serum proteins in short incubation times and is highly reproducible and amenable to an automated platform. Additionally, we show that this workflow may be combined in tandem with many different types of bead fractionation surfaces. Furthermore, by utilizing two different pooled human serum sample cohorts as proof-of-concept experiments, we are able to demonstrate the reproducibility of this method in the profiling of clinical samples and the ease of differential peptide identity determination. Overall, this method is an attractive strategy for high-throughput serum profiling with the goal of detecting and identifying differential peptides

A Robust and Universal Metaproteomics Workflow for Research Studies and Routine Diagnostics Within 24 h Using Phenol Extraction, FASP Digest, and the MetaProteomeAnalyzer

The investigation of microbial proteins by mass spectrometry (metaproteomics) is a key technology for simultaneously assessing the taxonomic composition and the functionality of microbial communities in medical, environmental, and biotechnological applications. We present an improved metaproteomics workflow using an updated sample preparation and a new version of the MetaProteomeAnalyzer software for data analysis. High resolution by multidimensional separation (GeLC, MudPIT) was sacrificed to aim at fast analysis of a broad range of different samples in less than 24 h. The improved workflow generated at least two times as many protein identifications than our previous workflow, and a drastic increase of taxonomic and functional annotations. Improvements of all aspects of the workflow, particularly the speed, are first steps toward potential routine clinical diagnostics (i.e., fecal samples) and analysis of technical and environmental samples. The MetaProteomeAnalyzer is provided to the scientific community as a central remote server solution at www.mpa.ovgu.de.Peer Reviewe

FLASH: ultra-fast protocol to identify RNA-protein interactions in cells

Determination of the in vivo binding sites of RNA-binding proteins (RBPs) is paramount to understanding their function and how they affect different aspects of gene regulation. With hundreds of RNA-binding proteins identified in human cells, a flexible, high-resolution, high-throughput, highly multiplexible and radioactivity-free method to determine their binding sites has not been described to date. Here we report FLASH (Fast Ligation of RNA after some sort of Affinity Purification for High-throughput Sequencing), which uses a special adapter design and an optimized protocol to determine protein-RNA interactions in living cells. The entire FLASH protocol, starting from cells on plates to a sequencing library, takes 1.5 days. We demonstrate the flexibility, speed and versatility of FLASH by using it to determine RNA targets of both tagged and endogenously expressed proteins under diverse conditions in vivo

Vortex fluidics-mediated DNA rescue from formalin-fixed museum specimens.

DNA from formalin-preserved tissue could unlock a vast repository of genetic information stored in museums worldwide. However, formaldehyde crosslinks proteins and DNA, and prevents ready amplification and DNA sequencing. Formaldehyde acylation also fragments the DNA. Treatment with proteinase K proteolyzes crosslinked proteins to rescue the DNA, though the process is quite slow. To reduce processing time and improve rescue efficiency, we applied the mechanical energy of a vortex fluidic device (VFD) to drive the catalytic activity of proteinase K and recover DNA from American lobster tissue (Homarus americanus) fixed in 3.7% formalin for >1-year. A scan of VFD rotational speeds identified the optimal rotational speed for recovery of PCR-amplifiable DNA and while 500+ base pairs were sequenced, shorter read lengths were more consistently obtained. This VFD-based method also effectively recovered DNA from formalin-preserved samples. The results provide a roadmap for exploring DNA from millions of historical and even extinct species

The EpiTect Methyl qPCR Assay as novel age estimation method in forensic biology

Human aging is associated with epigenetic modification of the genome. DNA methylation at cytosines appears currently as the best characterised modification that occurs during the mammalian lifetime. Such methylation changes at regulatory region can provide insights to track contributor age for criminal investigation. The EpiTect Methyl II PCR system (QIAGEN) was used to compare methylation levels of CpG islands in the promoter regions of a number of age related genes, of which four successfully showed changes across the lifespan (NPTX2, KCNQ1DN, GRIA2 and TRIM58). This technique is based on the detection of remaining input genome after digestion with a methylation-sensitive restriction enzyme. This study examined DNA specimens from 80 female subjects of various ages (18-91 years) obtained from blood, using primers designed to flank the studied gene loci. The data obtained from DNA methylation quantification showed successful discrimination among volunteered ages. Overall, the difference between predicted and real age was about 11 years and absolute mean differences (AMD) was only 7.2 years error. We suggest the EpiTect system can be used as fast and simple innovative tool in future forensic age estimation

A Robust, Simple Genotyping-by-Sequencing (GBS) Approach for High Diversity Species

Advances in next generation technologies have driven the costs of DNA sequencing down to the point that genotyping-by-sequencing (GBS) is now feasible for high diversity, large genome species. Here, we report a procedure for constructing GBS libraries based on reducing genome complexity with restriction enzymes (REs). This approach is simple, quick, extremely specific, highly reproducible, and may reach important regions of the genome that are inaccessible to sequence capture approaches. By using methylation-sensitive REs, repetitive regions of genomes can be avoided and lower copy regions targeted with two to three fold higher efficiency. This tremendously simplifies computationally challenging alignment problems in species with high levels of genetic diversity. The GBS procedure is demonstrated with maize (IBM) and barley (Oregon Wolfe Barley) recombinant inbred populations where roughly 200,000 and 25,000 sequence tags were mapped, respectively. An advantage in species like barley that lack a complete genome sequence is that a reference map need only be developed around the restriction sites, and this can be done in the process of sample genotyping. In such cases, the consensus of the read clusters across the sequence tagged sites becomes the reference. Alternatively, for kinship analyses in the absence of a reference genome, the sequence tags can simply be treated as dominant markers. Future application of GBS to breeding, conservation, and global species and population surveys may allow plant breeders to conduct genomic selection on a novel germplasm or species without first having to develop any prior molecular tools, or conservation biologists to determine population structure without prior knowledge of the genome or diversity in the species

Development of Oligonucleotide Microarray for High Throughput Dna Methylation Analysis

DNA methylation is a key event regulating gene expression. DNA methylation analysis plays a pivotal role in unlocking association of epigenetic events with cancer. However, simultaneous evaluation of the methylation status of multiple genes is still a technical challenge. Microarray is a promising approach for high-throughput analysis of the methylation status at numerous CpG sites within multiple genes of interest. In this dissertation study, we conducted a systematic study to examine the use of microarray methods for methylation analysis. First, a robust universal microarray was established with more flexible in design and content, and potential cost saving over commercial arrays. In order to produce high quality microarray data, we optimized the attachment chemistry for the modified oligonucleotides, searched for the good combination of fluorescent dyes, and hybridization conditions. To improve the specificity of the microarray, we conducted a study to experimentally search for a set of highly discriminative tag Sequences. Second, SBE-TAGs microarray was successfully adapted from the SNP detection for methylation analysis of multiple genes. SBE-TAGs microarray performed quite well in multiplex methylation analysis of cell lines if a standard calibration curve method was used. 10 CpG sites of 9 tumor suppressor genes (MGMT, GATA4, HLTF, SOCS1, p16, RASSF2, CHFR, TPEF, and Reprimo) were selected for this study. Third, a novel method called CHZMA (Competing-Hybridization- Zipcode-MicroArray) was developed for methylation analysis of tumor tissue samples, which is based on two steps of hybridization to achieve the specific detection of methylation on microarray. On the basis of analysis of seven genes (MGMT, GATA4, HLTF, SOCS1, RASSF2, ER, 3-OST-2), we found that the CHZMA assay can robustly detect methylation of multiple genes in the samples containing as low as 10 of methylated DNA. With the strict control group test and statistical analysis, CHZMA can be a good high-throughput method in place of MSP for meth

Development of Oligonucleotide Microarray for High Throughput Dna Methylation Analysis

DNA methylation is a key event regulating gene expression. DNA methylation analysis plays a pivotal role in unlocking association of epigenetic events with cancer. However, simultaneous evaluation of the methylation status of multiple genes is still a technical challenge. Microarray is a promising approach for high-throughput analysis of the methylation status at numerous CpG sites within multiple genes of interest. In this dissertation study, we conducted a systematic study to examine the use of microarray methods for methylation analysis. First, a robust universal microarray was established with more flexible in design and content, and potential cost saving over commercial arrays. In order to produce high quality microarray data, we optimized the attachment chemistry for the modified oligonucleotides, searched for the good combination of fluorescent dyes, and hybridization conditions. To improve the specificity of the microarray, we conducted a study to experimentally search for a set of highly discriminative tag Sequences. Second, SBE-TAGs microarray was successfully adapted from the SNP detection for methylation analysis of multiple genes. SBE-TAGs microarray performed quite well in multiplex methylation analysis of cell lines if a standard calibration curve method was used. 10 CpG sites of 9 tumor suppressor genes (MGMT, GATA4, HLTF, SOCS1, p16, RASSF2, CHFR, TPEF, and Reprimo) were selected for this study. Third, a novel method called CHZMA (Competing-Hybridization- Zipcode-MicroArray) was developed for methylation analysis of tumor tissue samples, which is based on two steps of hybridization to achieve the specific detection of methylation on microarray. On the basis of analysis of seven genes (MGMT, GATA4, HLTF, SOCS1, RASSF2, ER, 3-OST-2), we found that the CHZMA assay can robustly detect methylation of multiple genes in the samples containing as low as 10 of methylated DNA. With the strict control group test and statistical analysis, CHZMA can be a good high-throughput method in place of MSP for meth