Genetic Processes Commons^™

Mutations In Hcfc1 And Ronin Result In An Inborn Error Of Cobalamin Metabolism And Ribosomopathy, Tiffany Chern, Annita Achilleos, Xuefei Tong, Matthew C Hill, Alexander B Saltzman, Lucas C Reineke, Arindam Chaudhury, Swapan K Dasgupta, Yushi Redhead, David Watkins, Joel R Neilson, Perumal Thiagarajan, Jeremy B A Green, Anna Malovannaya, James F Martin, David S Rosenblatt, Ross A Poché

Faculty, Staff and Students Publications

Combined methylmalonic acidemia and homocystinuria (cblC) is the most common inborn error of intracellular cobalamin metabolism and due to mutations in Methylmalonic Aciduria type C and Homocystinuria (MMACHC). Recently, mutations in the transcriptional regulators HCFC1 and RONIN (THAP11) were shown to result in cellular phenocopies of cblC. Since HCFC1/RONIN jointly regulate MMACHC, patients with mutations in these factors suffer from reduced MMACHC expression and exhibit a cblC-like disease. However, additional de-regulated genes and the resulting pathophysiology is unknown. Therefore, we have generated mouse models of this disease. In addition to exhibiting loss of Mmachc, metabolic perturbations, and developmental defects previously …

Unique Challenges To Diagnosing Human Herpesvirus-6 (Hhv-6) Encephalitis Following Post-Hematopoietic Stem Cell Transplant: A Case And Brief Review, Harrison Zhu, Amir Ali, Karrune V Woan, Eric Tam, George Yaghmour, Alan Flores, Preet Chaudhary

Faculty, Staff and Students Publications

A patient with an ultimate diagnosis of human herpesvirus-6 (HHV-6) encephalitis developed central nervous system (CNS) symptoms 13 days after undergoing myeloablative haploidentical allogeneic hematopoietic stem cell transplant (HSCT). Due to the patient's body habitus, magnetic resonance (MR) imaging was not obtained until the onset of retrograde amnesia on day +24. MR imaging and other clinical findings eliminated all skepticism of HHV-6 encephalitis and HHV-6 antivirals were initiated on day +28, leading to gradual recovery. This case demonstrates some of the factors that may complicate the diagnosis of post-alloHSCT HHV-6 encephalitis. Because HHV-6 encephalitis and viremia can occur without warning, …

Single-Cell Rna Sequencing Reveals Intratumoral Heterogeneity And Potential Mechanisms Of Malignant Progression In Prostate Cancer With Perineural Invasion, Bao Zhang, Shenghan Wang, Zhichao Fu, Qiang Gao, Lin Yang, Zhentao Lei, Yuqiang Shi, Kai Le, Jie Xiong, Siyao Liu, Jiali Zhang, Junyan Su, Jing Chen, Mengyuan Liu, Beifang Niu

Faculty, Staff and Student Publications

Background: Prostate cancer (PCa) is the second most common cancer among men worldwide. Perineural invasion (PNI) was a prominent characteristic of PCa, which was recognized as a key factor in promoting PCa progression. As a complex and heterogeneous disease, its true condition is difficult to explain thoroughly with conventional bulk RNA sequencing. Thus, an improved understanding of PNI-PCa progression at the single-cell level is needed.

Methods: In this study, we performed scRNAseq on tumor tissues of three PNI-PCa patients. Principal component analysis (PCA) and Uniform manifold approximation and projection (UMAP) were used to reduce dimensionality and visualize the cellular composition …

Genetic Testing In Ambulatory Cardiology Clinics Reveals High Rate Of Findings With Clinical Management Implications, David R Murdock, Eric Venner, Donna M Muzny, Ginger A Metcalf, Mullai Murugan, Trevor D Hadley, Varuna Chander, Paul S De Vries, Xiaoming Jia, Aliza Hussain, Ali M Agha, Aniko Sabo, Shoudong Li, Qingchang Meng, Jianhong Hu, Xia Tian, Michelle Cohen, Victoria Yi, Christie L Kovar, Marie-Claude Gingras, Viktoriya Korchina, Chad Howard, Daniel L Riconda, Stacey Pereira, Hadley S Smith, Zohra A Huda, Alexandria Buentello, Patricia R Marino, Lee Leiber, Ashok Balasubramanyam, Christopher I Amos, Andrew B Civitello, Mihail G Chelu, Ronald Maag, Amy L Mcguire, Eric Boerwinkle, Xander H T Wehrens, Christie M Ballantyne, Richard A Gibbs

Faculty, Staff and Students Publications

PURPOSE: Cardiovascular disease (CVD) is the leading cause of death in adults in the United States, yet the benefits of genetic testing are not universally accepted.

METHODS: We developed the "HeartCare" panel of genes associated with CVD, evaluating high-penetrance Mendelian conditions, coronary artery disease (CAD) polygenic risk, LPA gene polymorphisms, and specific pharmacogenetic (PGx) variants. We enrolled 709 individuals from cardiology clinics at Baylor College of Medicine, and samples were analyzed in a CAP/CLIA-certified laboratory. Results were returned to the ordering physician and uploaded to the electronic medical record.

RESULTS: Notably, 32% of patients had a genetic finding with clinical …

Nrf1 Association With Auts2-Polycomb Mediates Specific Gene Activation In The Brain, Sanxiong Liu, Kimberly A Aldinger, Chi Vicky Cheng, Takae Kiyama, Mitali Dave, Hanna K Mcnamara, Wukui Zhao, James M Stafford, Nicolas Descostes, Pedro Lee, Stefano G Caraffi, Ivan Ivanovski, Edoardo Errichiello, Christiane Zweier, Orsetta Zuffardi, Michael Schneider, Antigone S Papavasiliou, M Scott Perry, Jennifer Humberson, Megan T Cho, Astrid Weber, Andrew Swale, Tudor C Badea, Chai-An Mao, Livia Garavelli, William B Dobyns, Danny Reinberg

Faculty, Staff and Student Publications

The heterogeneous family of complexes comprising Polycomb repressive complex 1 (PRC1) is instrumental for establishing facultative heterochromatin that is repressive to transcription. However, two PRC1 species, ncPRC1.3 and ncPRC1.5, are known to comprise novel components, AUTS2, P300, and CK2, that convert this repressive function to that of transcription activation. Here, we report that individuals harboring mutations in the HX repeat domain of AUTS2 exhibit defects in AUTS2 and P300 interaction as well as a developmental disorder reflective of Rubinstein-Taybi syndrome, which is mainly associated with a heterozygous pathogenic variant in CREBBP/EP300. Moreover, the absence of AUTS2 or mutation in its …

How Opportune Is Multigene Testing In Metastatic Colorectal Cancer? A Review, Cristina Orlov-Slavu, Andreea Parosanu, Mihaela Olaru, Dragos Serban, Ioana Paunica, Cornelia Nitipir

Journal of Mind and Medical Sciences

Personalized treatment in oncology is the most innovative method of care. The best method to establish personalized treatment is by genetic characterization of the malignant cell.

Theoretically, the more detailed the characterization, the more effective the choice of treatment becomes. Currently, there are fast and relatively low-cost options that allow such genetic characterization. However, test results sometimes do not detect targetable alterations and, even if they do detect, the use of the treatment-alteration combination does not always generate a satisfactory oncological response.

The present paper aims to answer two questions. First, how targetable can the most common gene alterations in …

Supercoiling And Looping Promote Dna Base Accessibility And Coordination Among Distant Sites, Jonathan M Fogg, Allison K Judge, Erik Stricker, Hilda L Chan, Lynn Zechiedrich

Faculty, Staff and Students Publications

DNA in cells is supercoiled and constrained into loops and this supercoiling and looping influence every aspect of DNA activity. We show here that negative supercoiling transmits mechanical stress along the DNA backbone to disrupt base pairing at specific distant sites. Cooperativity among distant sites localizes certain sequences to superhelical apices. Base pair disruption allows sharp bending at superhelical apices, which facilitates DNA writhing to relieve torsional strain. The coupling of these processes may help prevent extensive denaturation associated with genomic instability. Our results provide a model for how DNA can form short loops, which are required for many essential …

Discovery Of Potent Bet Bromodomain 1 Stereoselective Inhibitors Using Dna-Encoded Chemical Library Selections, Rajesh Sharma, Kyoung-Jae Choi, My Diem Quan, Sonum Sharma, Banumathi Sankaran, Hyekyung Park, Anel Lagrone, Jean J Kim, Kevin R Mackenzie, Allan Chris M Ferreon, Choel Kim, Josephine C Ferreon

Faculty, Staff and Students Publications

Expression of a few master transcription factors can reprogram the epigenetic landscape and three-dimensional chromatin topology of differentiated cells and achieve pluripotency. During reprogramming, thousands of long-range chromatin contacts are altered, and changes in promoter association with enhancers dramatically influence transcription. Molecular participants at these sites have been identified, but how this re-organization might be orchestrated is not known. Biomolecular condensation is implicated in subcellular organization, including the recruitment of RNA polymerase in transcriptional activation. Here, we show that reprogramming factor KLF4 undergoes biomolecular condensation even in the absence of its intrinsically disordered region. Liquid-liquid condensation of the isolated KLF4 …

Multiplexed Drug-Based Selection And Counterselection Genetic Manipulations In Drosophila, Nick Matinyan, Mansi S Karkhanis, Yezabel Gonzalez, Antrix Jain, Alexander Saltzman, Anna Malovannaya, Alejandro Sarrion-Perdigones, Herman A Dierick, Koen J T Venken

Faculty, Staff and Students Publications

The power of Drosophila melanogaster as a model system relies on tractable germline genetic manipulations. Despite Drosophila's expansive genetics toolbox, such manipulations are still accomplished one change at a time and depend predominantly on phenotypic screening. We describe a drug-based genetic platform consisting of four selection and two counterselection markers, eliminating the need to screen for modified progeny. These markers work reliably individually or in combination to produce specific genetic outcomes. We demonstrate three example applications of multiplexed drug-based genetics by generating (1) transgenic animals, expressing both components of binary overexpression systems in a single transgenesis step; (2) dual selectable …

Gene Expression Profiling Of Mapk Pathway Inhibitor Resistance In Cutaneous Melanoma: Can Bioinformatics Be Used To Select Better Melanoma Cell Lines?, Stephen Luebker

Theses & Dissertations

Melanoma is the deadliest form of skin cancer, and incidence has continued to increase. Half of all melanomas have a BRAF V600E mutation and respond to MAPK pathway inhibitors, including BRAF inhibitor therapy or BRAF/MEK inhibitor combination therapy, but nearly all patients develop treatment resistance. Melanoma cell lines produce variable results as models of MAPK pathway inhibitor resistance. To better understand how the genomic similarity of a melanoma cell line to patient-derived tumors affects resistance mechanisms, differences in DNA mutations and copy-number alterations were compared between melanoma cell lines profiled by the Cancer Cell Line Encyclopedia and cutaneous melanoma tumors …

Cyclic Amp Is Dispensable For Allorecognition In Dictyostelium Cells Overexpressing Pka-C, Shigenori Hirose, Mariko Katoh-Kurasawa, Gad Shaulsky

Faculty, Staff and Students Publications

Allorecognition and tissue formation are interconnected processes that require signaling between matching pairs of the polymorphic transmembrane proteins TgrB1 and TgrC1 in Dictyostelium. Extracellular and intracellular cAMP signaling are essential to many developmental processes. The three adenylate cyclase genes, acaA, acrA and acgA are required for aggregation, culmination and spore dormancy, respectively, and some of their functions can be suppressed by activation of the cAMP-dependent protein kinase PKA. Previous studies have suggested that cAMP signaling might be dispensable for allorecognition and tissue formation, while others have argued that it is essential throughout development. Here, we show that allorecognition and tissue …

Targeting The Apoa1 Locus For Liver-Directed Gene Therapy, Marco De Giorgi, Ang Li, Ayrea Hurley, Mercedes Barzi, Alexandria M Doerfler, Nikitha A Cherayil, Harrison E Smith, Jonathan D Brown, Charles Y Lin, Karl-Dimiter Bissig, Gang Bao, William R Lagor

Faculty, Staff and Students Publications

Clinical application of somatic genome editing requires therapeutics that are generalizable to a broad range of patients. Targeted insertion of promoterless transgenes can ensure that edits are permanent and broadly applicable while minimizing risks of off-target integration. In the liver, the Albumin (Alb) locus is currently the only well-characterized site for promoterless transgene insertion. Here, we target the Apoa1 locus with adeno-associated viral (AAV) delivery of CRISPR-Cas9 and achieve rates of 6% to 16% of targeted hepatocytes, with no evidence of toxicity. We further show that the endogenous Apoa1 promoter can drive robust and sustained expression of therapeutic …

A Method To Delineate De Novo Missense Variants Across Pathways Prioritizes Genes Linked To Autism, Amanda Koire, Panagiotis Katsonis, Young Won Kim, Christie Buchovecky, Stephen J Wilson, Olivier Lichtarge

Faculty, Staff and Students Publications

Genotype-phenotype relationships shape health and population fitness but remain difficult to predict and interpret. Here, we apply an evolutionary action method in mutational landscapes to unravel genes and pathways connected to autism spectrum disorder (ASD). Evolutionary action predicts the impact of missense variants on protein function by measuring motions in fitness landscapes, based on phylogenetic distances and substitution odds in homologous sequences. By examining 368 pathways across 2,384 individuals with ASD (probands), we found that 23 pathways, a total of 398 genes, had de novo missense variants biased to higher evolutionary action scores than expected by random chance, including axonogenesis, …

Genetic Correlates In Patients With Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia Treated With Hyper-Cvad/Hyper-Cmad Plus Dasatinib Or Hyper-Cvad Plus Ponatinib, Yuya Sasaki Md, Phd, Hagop Kantarjian Md, Nicholas J. Short Md, Farhad Ravandi Md, Marina Konopleva Md, Phd, Guillermo Garcia-Manero Md, Andrew Futreal, Feng Wang, Koichi Takahashi Md, Phd, Elias Jabbour Md

Education Week Poster Showcase 2021

Department of Leukemia Research

Department of Leukemia

Department of Genomic Medicine

Discovery And Characterization Of Bromodomain 2-Specific Inhibitors Of Brdt, Zhifeng Yu, Angela F Ku, Justin L Anglin, Rajesh Sharma, Melek Nihan Ucisik, John C Faver, Feng Li, Pranavanand Nyshadham, Nicholas Simmons, Kiran L Sharma, Sureshbabu Nagarajan, Kevin Riehle, Gundeep Kaur, Banumathi Sankaran, Marta Storl-Desmond, Stephen S Palmer, Damian W Young, Choel Kim, Martin M Matzuk

Faculty, Staff and Students Publications

Bromodomain testis (BRDT), a member of the bromodomain and extraterminal (BET) subfamily that includes the cancer targets BRD2, BRD3, and BRD4, is a validated contraceptive target. All BET subfamily members have two tandem bromodomains (BD1 and BD2). Knockout mice lacking BRDT-BD1 or both bromodomains are infertile. Treatment of mice with JQ1, a BET BD1/BD2 nonselective inhibitor with the highest affinity for BRD4, disrupts spermatogenesis and reduces sperm number and motility. To assess the contribution of each BRDT bromodomain, we screened our collection of DNA-encoded chemical libraries for BRDT-BD1 and BRDT-BD2 binders. High-enrichment hits were identified and resynthesized off-DNA and examined …

Dnp Final Report: Breaking The Cycle: Care Coordination Interventions And Sickle Cell Readmissions, Naphtali Edge

DNP Final Reports

Background

Approximately 100,000 people in the United States are affected by Sickle Cell Disease (SCD). Sickle Cell Disease represents the second highest readmitting diagnosis at Houston Methodist Hospital. The purpose of this study is to determine the impact of implementing care coordination interventions to reduce hospital readmissions of patients with SCD.

PICOT

In adult patients with SCD in the acute care hospital setting, how does care coordination intervention compared to no care coordination intervention affect the readmission rate for patients with SCD over a 3 – 6-month period?

Body of Evidence

Eleven studies were critical appraised and included in the …

Hospital-Acquired Venous Thromboembolism Or Bleeding Following Total Joint Arthroplasty: A Systematic Review And Meta-Analysis For The Association Of The Gene Polymorphism., Michael Debeau

Medical Student Research Symposium

This review seeks to understand the current existing literature on genetic polymorphisms to VTE following orthopedic surgery. Using PRISMA guidelines, 234 studies were retrieved from PubMed and Cochrane. The eligibility assessment yielded 16 studies including a systematic review. A STREGA and STROBE quality assessment found these studies to have high methodological quality. A significant association was found between the PAI-1 4G/4G genotype and resistance to anticoagulation therapy (OR = 2.692; 95% CI = 1.302 - 4.702). Moreover, the MTHFR C677T and A1298C polymorphisms significantly increased the incidence of VTE in patients that are compound heterozygotes (OR = 2.89; 95% CI …

Investigating The Role Of Znf384 Rearrangements In Acute Leukemia, Kirsten Dickerson

Theses and Dissertations (ETD)

Chromosomal rearrangements involving ZNF384 are the defining lesion in 5% of pediatric and adult B-cell acute lymphoblastic leukemia and tumors are characterized by aberrant myeloid marker expression. Additionally, ZNF384 rearrangements are the defining lesion in nearly half of pediatric B/myeloid mixed phenotype acute leukemia. These fusions juxtapose full-length ZNF384 to the N terminal portion of a diverse range of partners, most often, transcription factors or epigenetic modifiers. It has been shown that ZNF384-rearranged tumors have a distinct gene expression profile that is consistent between disease groups and N terminal partners. Genomic analyses of patient tumors has shown that ZNF384 fusions …

Moderate Heat-Assisted Gene Electrotransfer As A Potential Delivery Approach For Protein Replacement Therapy Through The Skin, Chelsea Edelblute, Cathryn Mangiamele, Richard Heller

Bioelectrics Publications

Gene-based approaches for protein replacement therapies have the potential to reduce the number of administrations. Our previous work demonstrated that expression could be enhanced and/or the applied voltage reduced by preheating the tissue prior to pulse administration. In the current study, we utilized our 16-pin multi-electrode array (MEA) and incorporated nine optical fibers, connected to an infrared laser, between each set of four electrodes to heat the tissue to 43 °C. For proof of principle, a guinea pig model was used to test delivery of reporter genes. We observed that when the skin was preheated, it was possible to achieve …

Open Problems In Extracellular Rna Data Analysis: Insights From An Ercc Online Workshop, Roger P Alexander, Robert R Kitchen, Juan Pablo Tosar, Matthew Roth, Pieter Mestdagh, Klaas E A Max, Joel Rozowsky, Karolina Elżbieta Kaczor-Urbanowicz, Justin Chang, Leonora Balaj, Bojan Losic, Eric L Van Nostrand, Emily Laplante, Bogdan Mateescu, Brian S White, Rongshan Yu, Aleksander Milosavljevic, Gustavo Stolovitzky, Ryan M Spengler

Faculty, Staff and Students Publications

We now know RNA can survive the harsh environment of biofluids when encapsulated in vesicles or by associating with lipoproteins or RNA binding proteins. These extracellular RNA (exRNA) play a role in intercellular signaling, serve as biomarkers of disease, and form the basis of new strategies for disease treatment. The Extracellular RNA Communication Consortium (ERCC) hosted a two-day online workshop (April 19–20, 2021) on the unique challenges of exRNA data analysis. The goal was to foster an open dialog about best practices and discuss open problems in the field, focusing initially on small exRNA sequencing data. Video recordings of workshop …

Identification Of Deep-Intronic Splice Mutations In A Large Cohort Of Patients With Inherited Retinal Diseases, Xinye Qian, Jun Wang, Meng Wang, Austin D Igelman, Kaylie D Jones, Yumei Li, Keqing Wang, Kerry E Goetz, David G Birch, Paul Yang, Mark E Pennesi, Rui Chen

Faculty, Staff and Students Publications

High throughput sequencing technologies have revolutionized the identification of mutations responsible for a diverse set of Mendelian disorders, including inherited retinal disorders (IRDs). However, the causal mutations remain elusive for a significant proportion of patients. This may be partially due to pathogenic mutations located in non-coding regions, which are largely missed by capture sequencing targeting the coding regions. The advent of whole-genome sequencing (WGS) allows us to systematically detect non-coding variations. However, the interpretation of these variations remains a significant bottleneck. In this study, we investigated the contribution of deep-intronic splice variants to IRDs. WGS was performed for a cohort …

Novel Mutations In The Gtpbp3 Gene For Mitochondrial Disease And Characteristics Of Related Phenotypic Spectrum: The First Three Cases From China, Hui-Ming Yan, Zhi-Mei Liu, Bei Cao, Victor Wei Zhang, Yi-Duo He, Zheng-Jun Jia, Hui Xi, Jing Liu, Fang Fang, Hua Wang

Faculty, Staff and Students Publications

Combined Oxidative Phosphorylation Deficiency 23 (COXPD23) caused by mutations in GTPBP3 gene is a rare mitochondrial disease, and this disorder identified from the Chinese population has not been described thus far. Here, we report a case series of three patients with COXPD23 caused by GTPBP3 mutations, from a severe to a mild phenotype. The main clinical features of these patients include lactic acidosis, myocardial damage, and neurologic symptoms. Whole genome sequencing and targeted panels of candidate human mitochondrial genome revealed that patient 1 was a compound heterozygote with novel mutations c.413C > T (p. A138V) and c.509_510del (p. E170Gfs∗42) in GTPBP3 …

A Case Of Simpson-Golabi-Behmel Syndrome Presenting With Cutaneous Findings, Tessa Mullins, Abigail Russell, Chad Johnston

HCA Healthcare Journal of Medicine

Simpson-Golabi-Behmel syndrome is a rare, X-linked recessive syndrome associated with mutations in the genes encoding glypican 3 (GPC3). The majority of cases have been described in pediatric males, with those affected showing manifestations of overgrowth, congenital heart defects, and increased incidence of neoplasia. Due to the X-linked nature of this disorder, penetrance is not well understood in female cases. Very few cases of female presentations of Simpson-Golabi-Behmel syndrome have been described, and this case highlights that there may be an association between mutated GPC3 carrier status and other cancers. We present a case of GPC3 gene mutation suggestive …

Pathway‐Extended Gene Expression Signatures Integrate Novel Biomarkers That Improve Predictions Of Patient Responses To Kinase Inhibitors, Ashis Bagchee‐Clark, Eliseos J. Mucaki, Tyson Whitehead, Peter Rogan

Biochemistry Publications

Cancer chemotherapy responses have been related to multiple pharmacogenetic biomarkers, often for the same drug. This study utilizes machine learning to derive multi‐gene expression signatures that predict individual patient responses to specific tyrosine kinase inhibitors, including erlotinib, gefitinib, sorafenib, sunitinib, lapatinib and imatinib. Support vector machine (SVM) learning was used to train mathematical models that distinguished sensitivity from resistance to these drugs using a novel systems biology‐based approach. This began with expression of genes previously implicated in specific drug responses, then expanded to evaluate genes whose products were related through biochemical pathways and interactions. Optimal pathway‐extended SVMs predicted responses in …

Causes Of Color Blindness: Function And Failure Of The Genes That Detect Color, Dylan Taylor

Senior Honors Theses

Color blindness affects nearly 10% of the entire population, with multiple types of color blindness from various genetic mutations. In the following sections, the nature of light and how the human eye perceives light will be discussed. Afterward, the major forms of color blindness and their genetic causes will be considered. Once these genetic causes have been established, the current method for diagnosing color blindness will be investigated, followed by a discussion of the current treatments available to those with color blindness. Finally, a brief discussion will address possible future work for color blindness with the hope of finding better …

Human Genes Differ By Their Uv Sensitivity Estimated Through Analysis Of Uv-Induced Silent Mutations In Melanoma, Ivan P Gorlov, Christopher I Amos, Spiridon Tsavachidis, Colin Begg, Eva Hernando, Chao Cheng, Ronglai Shen, Irene Orlow, Li Luo, Marc S Ernstoff, Joel Parker, Nancy E Thomas, Olga Y Gorlova, Marianne Berwick

Faculty, Staff and Students Publications

We hypothesized that human genes differ by their sensitivity to ultraviolet (UV) exposure. We used somatic mutations detected by genome-wide screens in melanoma and reported in the Catalog Of Somatic Mutations In Cancer. As a measure of UV sensitivity, we used the number of silent mutations generated by C>T transitions in pyrimidine dimers of a given transcript divided by the number of potential sites for this type of mutations in the transcript. We found that human genes varied by UV sensitivity by two orders of magnitude. We noted that the melanoma-associated tumor suppressor gene CDKN2A was among the top …

Versatile Phenotype-Activated Cell Sorting, Jihwan Lee, Zhuohe Liu, Peter H Suzuki, John F Ahrens, Shujuan Lai, Xiaoyu Lu, Sihui Guan, François St-Pierre

Faculty, Staff and Students Publications

Unraveling the genetic and epigenetic determinants of phenotypes is critical for understanding and re-engineering biology and would benefit from improved methods to separate cells based on phenotypes. Here, we report SPOTlight, a versatile high-throughput technique to isolate individual yeast or human cells with unique spatiotemporal profiles from heterogeneous populations. SPOTlight relies on imaging visual phenotypes by microscopy, precise optical tagging of single target cells, and retrieval of tagged cells by fluorescence-activated cell sorting. To illustrate SPOTlight's ability to screen cells based on temporal properties, we chose to develop a photostable yellow fluorescent protein for extended imaging experiments. We screened 3 …

Effects Of Germline And Somatic Events In Candidate Brca-Like Genes On Breast-Tumor Signatures, Weston R. Bodily, Brian H. Shirts, Tom Walsh, Suleyman Gulsuner, Mary-Claire King, Alyssa Parker, Moom Roosan, Stephen R. Piccolo

Pharmacy Faculty Articles and Research

Mutations in BRCA1 and BRCA2 cause deficiencies in homologous recombination repair (HR), resulting in repair of DNA double-strand breaks by the alternative non-homologous end-joining pathway, which is more error prone. HR deficiency of breast tumors is important because it is associated with better responses to platinum salt therapies and PARP inhibitors. Among other consequences of HR deficiency are characteristic somatic-mutation signatures and gene-expression patterns. The term “BRCA-like” (or “BRCAness”) describes tumors that harbor an HR defect but have no detectable germline mutation in BRCA1 or BRCA2. A better understanding of the genes and molecular events associated with tumors being …

The Ubiquitin Ligase Cullin-1 Associates With Chromatin And Regulates Transcription Of Specific C-Myc Target Genes, Melanie A Sweeney, Polina Iakova, Laure Maneix, Fu-Yuan Shih, Hannah E Cho, Ergun Sahin, Andre Catic

Faculty, Staff and Students Publications

Transcription is regulated through a dynamic interplay of DNA-associated proteins, and the composition of gene-regulatory complexes is subject to continuous adjustments. Protein alterations include post-translational modifications and elimination of individual polypeptides. Spatially and temporally controlled protein removal is, therefore, essential for gene regulation and accounts for the short half-life of many transcription factors. The ubiquitin-proteasome system is responsible for site- and target-specific ubiquitination and protein degradation. Specificity of ubiquitination is conferred by ubiquitin ligases. Cullin-RING complexes, the largest family of ligases, require multi-unit assembly around one of seven cullin proteins. To investigate the direct role of cullins in ubiquitination of …

A Substitution In Cgmp-Dependent Protein Kinase 1 Associated With Aortic Disease Induces An Active Conformation In The Absence Of Cgmp, Matthew H Chan, Sahar Aminzai, Tingfei Hu, Amatya Taran, Sheng Li, Choel Kim, Renate B Pilz, Darren E Casteel

Faculty, Staff and Students Publications

Type 1 cGMP-dependent protein kinases (PKGs) play important roles in human cardiovascular physiology, regulating vascular tone and smooth-muscle cell phenotype. A mutation in the human PRKG1 gene encoding cGMP-dependent protein kinase 1 (PKG1) leads to thoracic aortic aneurysms and dissections. The mutation causes an arginine-to-glutamine (RQ) substitution within the first cGMP-binding pocket in PKG1. This substitution disrupts cGMP binding to the pocket, but it also unexpectedly causes PKG1 to have high activity in the absence of cGMP via an unknown mechanism. Here, we identified the molecular mechanism whereby the RQ mutation increases basal kinase activity in the human PKG1α and …