13415 results for ""pdc"+"heritage+language"+census+study"

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• Mechanisms of Extreme Genomic Instability at Large Transcribed Genes

  Inhibiting DNA replication leads to copy number variant (CNV) formation throughout the genome, especially at chromosome fragile sites (CFSs). We previously showed that these hotspots for genome instability reside in late-replicating domains associated with large transcribed genes. In this study, we compared aphidicolin (APH)-induced CNV and CFS frequency between wild-type cells and isogenic cells in which FHIT gene transcription was ablated. We further examined the impact of altering RNase H1 expression on CNV or CFS induction frequency and analyzed R-loop formation genome-wide in a human fibroblast cell line. Data sets include Bru-seq nascent RNA transcription, whole genome sequencing for replication timing, SNP microarray analysis, and DRIP-seq. Results suggest that large gene transcription is a determining factor in replication stress-induced genomic instability and that CFSs mainly result from transcription-dependent passage of unreplicated DNA into mitosis with low R-loop levels observed at these loci.

  Study phs002066

• University of Miami Udall Center of Excellence Identification of Rare Variants in PD through Whole Exome Sequencing

  The focus of this study is to identify a new level of genetic variation, i.e. rare genetic variants with a population frequency less than 5%, usually less than 1%, which are believed to provide a stronger risk per variant than those studied to date in the large genome wide association studies (GWAS). To do this we are generating whole exome sequencing data on the Illumina HiSeq. Each HiSeq produces at least 600 billion base pairs of DNA sequence in one run. Whole exome sequencing sequence data, about 50 million base pairs, or about 1.5% of the total DNA of each person's genome, is generated. We are using this data to look for new DNA variations that give risk for Parkinson disease, as well as "modifiers", that may lead to having more severe or milder disease or later or earlier ages of onset.

  Study phs000908

• Genetic Determinants of EGFR-Driven Lung Cancer Growth and Therapeutic Response In Vivo

  Oncogenic alterations in EGFR frequently co-occur with additional genetic alterations in EGFR-driven lung adenocarcinoma (LUAD), but how specific combinations of mutations affect tumor phenotypes and responses to targeted therapy is yet unknown. We leveraged a genetically engineered mouse model of EGFR mutant/Trp53-deficient LUAD to study the consequences of inactivating 10 different tumor suppressor genes on the fitness and tyorosine kinase inhibitor (TKI) sensitivity of these tumors. We found that loss of Keap1 is associated with a reduced response to therapy. In patients, we found that mutations in the KEAP1/NFE2L2/CUL3 pathway are associated with a significantly shorter time to treatment failure for EGFR TKI therapy compared to matched patients with wild-type KEAP1/NFE2L2/CUL3 tumors. We also analyzed whole exome sequencing data from tumor specimens before TKI treatment and at the time of treatment resistance for mutations in the KEAP1 pathway and these data are being submitted here.  

  Study phs002334

• Transcriptomic Analysis of Human Hematopoietic Progenitors from Healthy Donors and Bone Marrow Failure Patients

  The purpose of this study was to define transcriptional changes that occur in the rare and heterogeneous bone marrow progenitors that are affected in Shwachman-Diamond Syndrome. Data are reported for four genetically confirmed SDS patients ranging from 11-26 years old, 3 male and 1 female, and four healthy donors ranging from 25-29 years old, 2 male and 2 female. Subjects provided written, informed consent in accordance with the Declaration of Helsinki's Ethical Principles of Medical Research Involving Human Subjects. Single CD34+ cells were purified from fresh bone marrow and cDNA libraries were prepared using the SMARTer Ultra Low RNA Kit (Clontech; pre-2015) or SMART-Seq v4 Ultra Low RNA Kit (Clontech; post-2015). Libraries were sequenced on a HiSeq 2500 Instrument (Illumina, San Diego, CA) to a read depth of ~3 M paired-end, 25 bp reads per single cell. Paired-end reads were mapped to the hg38 human transcriptome (Gencode v24) using STAR v2.4.2a.

  Study phs001845

• Molecular Analysis of Short- Versus Long-Term Survivors of High-Grade Serous Ovarian Carcinoma

  The underlying determinants for long-term survival (LTS, ≥10 years) versus short-term survival (STS, <3 years) of patients diagnosed with high-grade serous ovarian carcinoma (HGSC) are largely unknown. The present study sought to identify molecular predictors of LTS for women with HGSC. A cohort of 24 frozen HGSC samples (12 LTS and 12 STS) were collected and analyzed at DNA and RNA levels. Copy number variation and mutation did not indicate large differences between LTS and STS. From RNA-Seq analysis, 11 genes were found to be differentially expressed between the STS and LTS groups (fold change >2; false discovery rate <0.01). In the validation cohort, transmembrane protein 62 (TMEM62) was found to be related to LTS. Our in vitro and in vivo studies demonstrate that restoring TMEM62 may be a novel approach for treatment of HGSC. These findings may have implications for biomarker and intervention strategies to help improve patient outcomes.

  Study phs003020

• Differential Transcription Start Site Usage in Brain-related Samples

  RNA-Seq is an effective method to study the transcriptome, but specialized methods are required to identify 5' ends of transcripts. Several published strategies exist for this specific purpose, but their relative merits have not been systematically analyzed. Here, we directly compare the performance of six such methods - testing five with cellular RNA as well as a novel spike-in RNA assay that helps address interpretation challenges that arise from uncertainties in annotation or RNA processing. Using a single human RNA sample, we constructed and sequenced 18 libraries with these methods and one standard, control RNA-Seq library. We find that the CAGE method performed best for mRNA and that most of its unannotated peaks are supported by evidence from other genomic methods. We then applied CAGE to eight brain-related samples and revealed sample-specific transcription start site (TSS) usage as well as a transcriptome-wide shift in TSS usage between fetal and adult brain.

  Study phs001463

• Prospective Analysis of Genotypes in Adults Undergoing Therapy for Lung Cancer (Paclitaxel Cohort)

  Lung cancer is frequently treated with paclitaxel in combination with several other agents; however, paclitaxel treatment is often ineffective or limited by treatment-related toxicities. Heritable variants in genes associated with absorption, distribution, metabolism, and elimination may predict paclitaxel clinical outcome and toxicity. We designed a prospective multi-institutional study that recruited 546 patients receiving therapy with a 5-year follow up. All patients were genotyped using the Drug Metabolizing Enzymes and Transporters (DMET) platform, which ascertains 1931 genotypes in 235 genes. Genotypes were compared to the progression-free survival of paclitaxel therapy and clinically-significant paclitaxel toxicities. Seven genetic variants were associated with paclitaxel PFS (in ABCB11, ABCC3, ABCG1, CYP8B1, NR3C1, FMO6P, and GSTM3), whereas four genetic variants (in VKORC1, SLC22A14, GSTA2, and DCK) were associated with paclitaxel toxicities. The present SNPs have limited clinical utility but suggest that certain genes are related to important paclitaxel pathways in lung cancer.

  Study phs001660

• Integrated Single-Cell Genetic and Transcriptional Analysis Suggests Novel Drivers of Chronic Lymphocytic Leukemia

  Intratumoral genetic heterogeneity has been characterized across cancers by genome sequencing of bulk tumors, including chronic lymphocytic leukemia (CLL). In order to more accurately identify subclones, define phylogenetic relationships, and probe genotype-phenotype relationships, we developed methods for targeted mutation detection in DNA and RNA isolated from thousands of single cells from five CLL samples. By clearly resolving phylogenic relationships, we uncovered mutated LCP1 and WNK1 as novel CLL drivers, supported by functional evidence demonstrating their impact on CLL pathways. Integrative analysis of somatic mutations with transcriptional states prompts the idea that convergent evolution generates phenotypically similar cells in distinct genetic branches, thus creating a cohesive expression profile in each CLL sample despite the presence of genetic heterogeneity. Our study highlights the potential for single-cell RNA-based targeted analysis to sensitively determine transcriptional and mutational profiles of individual cancer cells leading to increased understanding of driving events in malignancy. Reprinted from Genome Research, with permission from Publisher.

  Study phs001372

• Mitochondrial Abnormalities in Schizophrenia and Bipolar Disorder

  Mitochondrial DNA structural variation is one proposed indicator of mitochondrial dysfunction. The large common deletion of mitochondrial DNA (mtDNA) increases with aging across multiple brain regions. We found other large deletions of mtDNA in brain at levels comparable to the common deletion (PMID: 30869147). Since mtDNA molecules replicate independently of nuclear division, the mtDNA copy number is a measure of mitochondrial health; levels are negatively correlated with age and all-cause morbidity. Complex I activity is another functional measure of mitochondria. We previously published a subset of this data from DLPFC (PMID: 29594135) for three indicators (common deletion, mtDNA copy number, Complex I activity). For this study, four indicators (common deletion, large deletions, mtDNA copy number, Complex I activity) were measured in four brain regions from subjects with schizophrenia (SZ) and bipolar disorder (BD) and compared to controls. The four brain regions were: the dorsolateral prefrontal cortex, superior temporal gyrus, primary visual cortex (V1), and nucleus accumbens.    

  Study phs002395

• Sequencing of Coding and Non-coding Regions in Primary Breast Cancers and Patient-matched Controls

  Genomic analysis of tumor samples has led to the identification of hundreds of cancer genes based on the presence of mutations in protein-coding regions. By contrast, much less is known about cancer-causing mutations in non-coding regions. Here, we performed deep sequencing in 360 primary breast cancers and developed computational methods to identify significantly mutated promoters. Clear signals were found in the promoters of four genes. FOXA1, a known driver of hormone-receptor positive breast cancer, harbors a mutational hotspot in its promoter that leads to overexpression through increased E2F binding. RMRP and NEAT1, two non-coding RNA genes, carry mutations that alter protein binding to the promoter and impact expression levels. Overall, our study shows that recurrent mutations in or near gene promoters in cancers have functional consequences. Power analyses indicate that more such genes remain to be discovered through deep sequencing of adequately sized patient cohorts.

  Study phs001250