Genetic Processes Commons^™

Infection And Transmission Determinants Of Flea-Borne Rickettsioses, Hanna J. Laukaitis

Graduate Theses and Dissertations (2019 - present)

The genus Rickettsia is comprised of Gram-negative, obligate intracellular bacteria that are spread by hematophagous arthropods. Elucidating the factors conferring rickettsial virulence has perplexed investigators for decades, complicated by the lack of efficient genetic tools necessary to uncover rickettsial- and vector-specific factors contributing to persistence. The advent of transposon mutagenesis has enabled the field to make vast developments in uncovering novel rickettsial mechanisms utilized in various host backgrounds. Thus, the aim of this study was to generate Rickettsia felis transposon mutants and characterize novel phenotypes associated with genetic disruption in an arthropod background. Distribution of rickettsiae is reliant on the …

Whole Genome Sequence Association Analysis Of Fasting Glucose And Fasting Insulin Levels In Diverse Cohorts From The Nhlbi Topmed Program, Daniel Dicorpo, Sheila M. Gaynor, Emily M. Russell, Kenneth E. Westerman, Laura M. Raffield, Marcio Almeida, Juan M. Peralta, John Blangero, Joanne E. Curran, Ravindranath Duggirala

School of Medicine Publications

The genetic determinants of fasting glucose (FG) and fasting insulin (FI) have been studied mostly through genome arrays, resulting in over 100 associated variants. We extended this work with high-coverage whole genome sequencing analyses from fifteen cohorts in NHLBI’s Trans-Omics for Precision Medicine (TOPMed) program. Over 23,000 non-diabetic individuals from five race-ethnicities/populations (African, Asian, European, Hispanic and Samoan) were included. Eight variants were significantly associated with FG or FI across previously identified regions MTNR1B, G6PC2, GCK, GCKR and FOXA2. We additionally characterize suggestive associations with FG or FI near previously identified SLC30A8, TCF7L2, and ADCY5 regions as well …

Structural Basis For The Simultaneous Recognition Of Nemo And Acceptor Ubiquitin By The Hoip Nzf1 Domain, Simin Rahighi, Mamta Iyer, Hamid Oveisi, Sammy Nasser, Vincent Duong

Pharmacy Faculty Articles and Research

Ubiquitination of NEMO by the linear ubiquitin chain assembly complex (LUBAC) is essential for activating the canonical NF-κB signaling pathway. While the NZF1 domain of the HOIP subunit of LUBAC recognizes the NEMO substrate, it is unclear how it cooperates with the catalytic domains in the ubiquitination process. Here, we report a crystal structure of NEMO in complex with HOIP NZF1 and linear diubiquitin chains, in which the two proteins bind to distinct sites on NEMO. Moreover, the NZF1 domain simultaneously interacts with NEMO and Ile44 surface of a proximal ubiquitin from a linear diubiquitin chain, where the C-term tail …

Synthesis And Evaluation Of Anti-Hiv Activity Of Mono- And Di-Substituted Phosphonamidate Conjugates Of Tenofovir, Aaminat Qureshi, Louise A. Ouattara, Naglaa Salem El-Sayed, Amita Verma, Gustavo F. Doncel, Muhammad Iqbal Choudhary, Hina Siddiqui, Keykavous Parang

Pharmacy Faculty Articles and Research

The activity of nucleoside and nucleotide analogs as antiviral agents requires phosphorylation by endogenous enzymes. Phosphate-substituted analogs have low bioavailability due to the presence of ionizable negatively-charged groups. To circumvent these limitations, several prodrug approaches have been proposed. Herein, we hypothesized that the conjugation or combination of the lipophilic amide bond with nucleotide-based tenofovir (TFV) (1) could improve the anti-HIV activity. During the current study, the hydroxyl group of phosphonates in TFV was conjugated with the amino group of L-alanine, L-leucine, L-valine, and glycine amino acids and other long fatty ester hydrocarbon chains to synthesize 43 derivatives. Several …

Genetic Risk, Midlife Life's Simple 7, And Incident Dementia In The Atherosclerosis Risk In Communities Study, Adrienne Tin, Jan Bressler, Jeannette Simino, Kevin J Sullivan, Hao Mei, B Gwen Windham, Michael Griswold, Rebecca F Gottesman, Eric Boerwinkle, Myriam Fornage, Thomas H Mosley

Faculty, Staff and Student Publications

BACKGROUND AND OBJECTIVES: Higher scores in Life's Simple 7 (LS7), a metric for cardiovascular and brain health, have been associated with lower risk of dementia. It is uncertain whether this association holds among those with high genetic risk of dementia. Our objective is to evaluate the extent that LS7 may offset dementia risk across the range of genetic risk.

METHODS: Participants in the Atherosclerosis Risk in Communities (ARIC) Study were followed from 1987-1989 to 2019. We derived midlife LS7 scores and generated genetic risk scores (GRS) using genome-wide summary statistics of Alzheimer disease, which have been used to study the …

Non-Alcoholic Fatty Liver Disease And Depression: Evidence For Genotype × Environment Interaction In Mexican Americans, Eron G. Manusov, Vincent P. Diego, Khalid Sheikh, Sandra Laston, John Blangero, Sarah Williams-Blangero

School of Medicine Publications

This study examines the impact of G × E interaction effects on non-alcoholic fatty liver disease (NAFLD) among Mexican Americans in the Rio Grande Valley (RGV) of South Texas. We examined potential G × E interaction using variance components models and likelihood-based statistical inference in the phenotypic expression of NAFLD, including hepatic steatosis and hepatic fibrosis (identified using vibration controlled transient elastography and controlled attenuation parameter measured by the FibroScan Device). We screened for depression using the Beck Depression Inventory-II (BDI-II). We identified significant G × E interactions for hepatic fibrosis × BDI-II. These findings provide evidence that genetic factors …

Identification Of Healthspan-Promoting Genes In Caenorhabditis Elegans Based On A Human Gwas Study, Nadine Saul, Ineke Dhondt, Mikko Kuokkanen, Markus Perola, Clara Verschuuren, Brecht Wouters, Henrik Von Chrzanowski, Winnok H. De Vos, Liesbet Temmerman, Walter Luyten

School of Medicine Publications

To find drivers of healthy ageing, a genome-wide association study (GWAS) was performed in healthy and unhealthy older individuals. Healthy individuals were defined as free from cardiovascular disease, stroke, heart failure, major adverse cardiovascular event, diabetes, dementia, cancer, chronic obstructive pulmonary disease (COPD), asthma, rheumatism, Crohn’s disease, malabsorption or kidney disease. Six single nucleotide polymorphisms (SNPs) with unknown function associated with ten human genes were identified as candidate healthspan markers. Thirteen homologous or closely related genes were selected in the model organism C. elegans for evaluating healthspan after targeted RNAi-mediated knockdown using pathogen resistance, muscle integrity, chemotaxis index and the …

Crispr/Cas13 Effectors Have Differing Extents Of Off-Target Effects That Limit Their Utility In Eukaryotic Cells, Yuxi Ai, Dongming Liang, Jeremy E Wilusz

Faculty, Staff and Students Publications

CRISPR/Cas13 effectors have garnered increasing attention as easily customizable tools for detecting and depleting RNAs of interest. Near perfect complementarity between a target RNA and the Cas13-associated guide RNA is required for activation of Cas13 ribonuclease activity. Nonetheless, the specificity of Cas13 effectors in eukaryotic cells has been debated as the Cas13 nuclease domains can be exposed on the enzyme surface, providing the potential for promiscuous cleavage of nearby RNAs (so-called collateral damage). Here, using co-transfection assays in Drosophila and human cells, we found that the off-target effects of RxCas13d, a commonly used Cas13 effector, can be as strong as …

Decoding The Pitx2-Controlled Genetic Network In Atrial Fibrillation, Jeffrey D Steimle, Francisco J Grisanti Canozo, Minjun Park, Zachary A Kadow, Md Abul Hassan Samee, James F Martin

Faculty, Staff and Students Publications

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia and a major risk factor for stroke, often arises through ectopic electrical impulses derived from the pulmonary veins (PVs). Sequence variants in enhancers controlling expression of the transcription factor PITX2, which is expressed in the cardiomyocytes (CMs) of the PV and left atrium (LA), have been implicated in AF predisposition. Single nuclei multiomic profiling of RNA and analysis of chromatin accessibility combined with spectral clustering uncovered distinct PV- and LA-enriched CM cell states. Pitx2-mutant PV and LA CMs exhibited gene expression changes consistent with cardiac dysfunction through cell type-distinct, PITX2-directed, cis-regulatory …

Leveraging Single Cell Technologies For The Characterization And Treatment Of Refractory Pancreatic Cancer, Maria Monberg

Dissertations and Theses (Open Access)

Heterogeneity is a hallmark of cancer, and the advent of multimodal single-cell technologies has helped uncover heterogeneity in a high-throughput manner in different cancers across varied contexts at an unprecedented resolution. In an effort to improve precision medicine approaches in pancreatic ductal adenocarcinoma (PDAC), a highly lethal malignancy with a mere 11% 5-year survival rate, this dissertation focuses on first questioning the assumptions of the most basic models used to study PDAC via multimodal single-cell characterization methods at multiple levels of biological organization (scCNVseq and snATACseq for DNA assays, scRNAseq for transcriptomics, and paired protein assays such as multiplexed immunofluorescence …

How Environmental Change Will Impact Mosquito-Borne Diseases, Arsal Khan

Master's Projects and Capstones

Mosquitos, the most lethal species throughout human history, are the most prevalent source of vector-borne diseases and therefore a major global health burden. Mosquito-borne disease incidence is expected to shift with environmental change. These changes can be predicted using species distribution models. With the wide variety of methods used for models, consensus for improving accuracy and comparability is needed. A comparative analysis of three recent modeling approaches revealed that integrating modeling techniques compensates for trade-offs associated with a singular approach. An area that represents a critical gap in our ability to predict mosquito behavior in response to changing climate factors, …

Systematic Expression Profiling Of Dpr And Dip Genes Reveals Cell Surface Codes In Drosophila Larval Motor And Sensory Neurons, Yupu Wang, Meike Lobb-Rabe, James Ashley, Purujit Chatterjee, Veera Anand, Hugo J Bellen, Oguz Kanca, Robert A Carrillo

Faculty, Staff and Students Publications

In complex nervous systems, neurons must identify their correct partners to form synaptic connections. The prevailing model to ensure correct recognition posits that cell-surface proteins (CSPs) in individual neurons act as identification tags. Thus, knowing what cells express which CSPs would provide insights into neural development, synaptic connectivity, and nervous system evolution. Here, we investigated expression of Dpr and DIP genes, two CSP subfamilies belonging to the immunoglobulin superfamily, in Drosophila larval motor neurons (MNs), muscles, glia and sensory neurons (SNs) using a collection of GAL4 driver lines. We found that Dpr genes are more broadly expressed than DIP genes …

Genetic Origins Of Polycystic Ovarian Syndrome (Pcos): An Analysis Of The Genetic Correlation Between Pcos And Insulin Receptor Mutations, Lauren Henry

Undergraduate Theses

Polycystic Ovarian Syndrome (PCOS) remains an extremely common, yet understudied syndrome experienced by 6-12% of females of reproductive age. Not only does it cause painful side effects manifesting both physically and mentally, but it also poses a threat to the fertility of those affected. For this reason, a more in-depth analysis to better understand how to detect this condition early and prevent fertility complications later is certainly warranted. PCOS is suspected to be primarily genetic due to correlations among immediate female family members. Based on previous research, a good starting point for analysis is the INSR gene. Various mutations within …

The Use Of Embark In Teaching About Genetic Relatedness, Anna Bonvillain, Tori Trammel

Honors Theses

Because of the increasing importance of precision medicine, it is vital that future healthcare providers master concepts related to genetic variation taught during their undergraduate classes. However, studies have shown that physicians often lack an adequate understanding of genetics, which serves as a hindrance to effectively caring for their patients. To address this issue, we created a collaborative active-learning protocol to improve pre-health students' comprehension of key concepts such as genetic relatedness and the source of genetic variation between siblings. Our worksheet guides students to compare the genetic profiles of two canine siblings using the Embark DNA genotyping platform. Embark …

Erα As A Modulator Of The Sle1b Lupus Susceptibility Locus And B Cell Receptor Signaling, Jared H. Graham

Theses & Dissertations

Systemic Lupus Erythematosus (SLE) is an autoimmune disease characterized by loss of immune tolerance and the production of anti-nuclear autoantibodies. 90% of lupus patients are women, and this sex bias is due to the actions of estrogens, which promote lupus pathogenesis. Our lab has shown that estrogen receptor alpha (ERα) mediates the effect of estrogens in lupus and that ERa acts in a B cell intrinsic manner to promote the development of autoantibodies and SLE. Genetic factors also contribute to lupus. One major lupus susceptibility locus, Sle1, controls loss of tolerance and autoantibody development as well as immune cell …

Conservation And Divergence In The Heterochronic Pathway Of C. Elegans And C. Briggsae, Maria Ivanova, Eric G. Moss

Rowan-Virtua Research Day

The heterochronic pathway of Caenorhabditis elegans is exemplary as a mechanism of developmental timing: mutations in genes of this pathway alter the relative timing of diverse developmental events independent of spatial or cell type specific regulation. It is the most thoroughly characterized developmental timing pathway known. Most of the heterochronic genes are conserved across great evolutionary time, and a few homologs seem to have developmental timing roles in certain contexts. The degree to which other organisms have explicit developmental timing mechanisms, and what factors comprise those mechanisms, isn’t generally known.

Developmental pathways evolve even if the resulting morphology remains the …

Modeling The Role Of Cyclin C In Connecting Stress-Induced Mitochondrial Fission To Apoptosis, Steven J. Doyle, Randy Strich

Rowan-Virtua Research Day

For normal cell function, exogenous signals must be correctly interpreted, and the proper response executed. The mitochondria are key regulatory nodes of cellular fate. For example, mitochondria undergo fission and fusion cycles depending on the energetic needs of the cell. Additionally, regulated cell death pathways also function at the mitochondria. Cyclin C is a transcriptional regulator of stress response and growth control genes. Following stress, a portion of cyclin C translocates to the cytoplasm, where it interacts with both the mitochondrial fission and apoptotic machinery. Based on these findings, we hypothesize that Cyclin C represents a key mediator linking transcription …

Substrate-Specific Effect On Sirtuin Conformation And Oligomerization, Jie Yang, Shannon L. Dwyer, Nathan I. Nicely, Brian P. Weiser

Rowan-Virtua Research Day

Human sirtuins are a family of nicotinamide adenine dinucleotide (NAD +)-dependent enzymes that are responsible for removing acyl modifications from lysine residues. Sirtuins are involved in the formation and proliferation of cancers and are thought to regulate the progression of neurodegenerative diseases. Although sirtuins can be pharmacologically targeted by small molecules, it is not easy to modulate the substrate selectivity of sirtuins despite the chemical diversity of their substrates. Here, we report substrate-specific effects on sirtuin conformation and oligomerization that regulate enzyme deacylase activity. We used fluorescent acyl peptide probes to study substrate interactions with two sirtuin isoforms: SIRT2 and …

Ung2 And Rpa Activity On Ssdna-Dsdna Junctions, Kathy Chen, Sharon Greenwood, Brian P. Weiser

Rowan-Virtua Research Day

Uracil DNA glycosylase, or UNG2, is an enzyme that is involved in DNA repair. Its primary job is to eliminate harmful uracil bases from DNA strands. To do this, the enzyme is assisted by replication protein A (RPA). RPA helps UNG2 in the identification of uracil bases by targeting UNG2 activity near ssDNA-dsDNA junctions (1-3). The results from assays presented here agree with published findings that showed UNG2 is heavily targeted by RPA to uracil bases that are close to ssDNA-dsDNA junctions (for example, uracil located 9 bps from the junction as opposed to 33 bps) (1,2). However, these previous …

Systems Biology Approach To Functionally Assess The Clostridioides Difficile Pangenome Reveals Genetic Diversity With Discriminatory Power, Charles J Norsigian, Heather A Danhof, Colleen K Brand, Firas S Midani, Jared T Broddrick, Tor C Savidge, Robert A Britton, Bernhard O Palsson, Jennifer K Spinler, Jonathan M Monk

Faculty, Staff and Students Publications

Combatting Clostridioides difficile infections, a dominant cause of hospital-associated infections with incidence and resulting deaths increasing worldwide, is complicated by the frequent emergence of new virulent strains. Here, we employ whole-genome sequencing, high-throughput phenotypic screenings, and genome-scale models of metabolism to evaluate the genetic diversity of 451 strains of C. difficile. Constructing the C. difficile pangenome based on this set revealed 9,924 distinct gene clusters, of which 2,899 (29%) are defined as core, 2,968 (30%) are defined as unique, and the remaining 4,057 (41%) are defined as accessory. We develop a strain typing method, sequence typing by accessory genome (STAG), …