Genetic Structures Commons^™

Mecp2 Interacts With The Super Elongation Complex To Regulate Transcription, Jun Young Sonn, Wonho Kim, Marta Iwanaszko, Yuki Aoi, Yan Li, Guantong Qi, Luke Parkitny, Janice L Brissette, Lorin Weiner, Juan Botas, Ismael Al-Ramahi, Ali Shilatifard, Huda Y Zoghbi

Faculty, Staff and Students Publications

Loss-of-function mutations in methyl-CpG binding protein 2 (MECP2) cause Rett syndrome. While we know that MeCP2 binds to methylated cytosines on DNA, the full breadth of the molecular mechanisms by which MeCP2 regulates gene expression remains incompletely understood. Here, using a genetic modifier screen, we identify the super elongation complex, a P-TEFb–containing elongation factor that releases promoter-proximally paused RNA polymerase II, as a genetic interactor of MECP2. MeCP2 physically interacts with SEC subunits and directly binds AFF4, the scaffold of the SEC, via the transcriptional repression domain. Furthermore, MeCP2 facilitates the binding of AFF4 on a subset …

Transcription-Replication Collisions Trigger High-Fidelity Replication Reset, Matthew B Cooke, Kobie T Welch, Laura Deus Ramirez, Katelin M Hagstrom, Alice X Wen, Jennifer A Halliday, Susan M Rosenberg, Christophe Herman

Faculty, Staff and Students Publications

Double-stranded DNA ends arise from external agents or cellular processes like transcription-replication collisions (TRCs), threatening genome stability. Here, we performed genomic CRISPRi screens to uncover DNA end formation factors in Escherichia coli. We discovered that translation-transcription decoupling causes DNA end formation through a TRC-dependent pathway, which is lethal when DNA end processing by RecBCD is disrupted, but not when recombination is disrupted. We find that TRCs cause replisome stalling followed by "rear-ending" from trailing replisomes which generates free DNA ends, rather than strand breaks. Surprisingly, these DNA ends are resolved through a process we call "replication reset", where the stalled …

Dna Methylation And Machine Learning: Challenges And Perspective Toward Enhanced Clinical Diagnostics, Erfan Aref-Eshghi, Arash B Abadi, Mohammad-Erfan Farhadieh, Amirreza Hooshmand, Fatemeh Ghasemi, Leila Youssefian, Hassan Vahidnezhad, Taylor Martin Kerrins, Xiaonan Zhao, Mahdi Akbarzadeh, Hakon Hakonarson, Amir Hossein Saeidian

Faculty, Staff and Students Publications

DNA methylation is an epigenetic modification that regulates gene expression by adding methyl groups to DNA, affecting cellular function and disease development. Machine learning, a subset of artificial intelligence, analyzes large datasets to identify patterns and make predictions. Over the past two decades, advances in bioinformatics technologies for arrays and sequencing have generated vast amounts of data, leading to the widespread adoption of machine learning methods for analyzing complex biological information for medical problems. This review explores recent advancements in DNA methylation studies that leverage emerging machine learning techniques for more precise, comprehensive, and rapid patient diagnostics based on DNA …

Improved Allele Frequencies In Gnomad Through Local Ancestry Inference, Pragati Kore, Michael W Wilson, Grace Tiao, Katherine Chao, Philip W Darnowsky, Nicholas A Watts, Jessica Honorato Mauer, Samantha M Baxter, Genome Aggregation Database Consortium, Heidi L Rehm, Mark J Daly, Konrad J Karczewski, Elizabeth G Atkinson

Faculty, Staff and Students Publications

The Genome Aggregation Database (gnomAD) is a foundational resource for allele frequency data, widely used in genomic research and clinical interpretation. However, traditional estimates rely on individual-level genetic ancestry groupings that may obscure variation in recently admixed populations. To improve resolution, we applied local ancestry inference (LAI) to over 27 million variants in two admixed groups: Admixed American (n = 7612) and African/African American (n = 20,250), deriving ancestry-specific allele frequencies. We show that 78.5% and 85.1% of variants in these groups, respectively, exhibit at least a twofold difference in ancestry-specific frequencies. Moreover, 81.49% of variants with LAI information would …

Mapping Mave Data For Use In Human Genomics Applications, Jeremy A Arbesfeld, Estelle Y Da, James S Stevenson, Kori Kuzma, Anika Paul, Tierra Farris, Benjamin J Capodanno, Sally B Grindstaff, Kevin Riehle, Nuno Saraiva-Agostinho, Jordan F Safer, Jonathan Casper, Maximilian Haeussler, Aleksandar Milosavljevic, Julia Foreman, Helen V Firth, Sarah E Hunt, Sumaiya Iqbal, Melissa S Cline, Alan F Rubin, Alex H Wagner

Faculty, Staff and Students Publications

Background: Experimental data from functional assays have a critical role in interpreting the impact of genetic variants. Assay data must be unambiguously mapped to a reference genome to make it accessible, but it is often reported relative to assay-specific sequences, complicating downstream use and integration of variant data across resources. To make multiplexed assays of variant effect (MAVE) data more broadly available to the research and clinical communities, the Atlas of Variant Effects Alliance mapped MAVE data from the MaveDB community database to human reference sequences, creating an extensive set of machine-readable homology mappings that are incorporated into widely used …

Genomic Balancing Act: Deciphering Dna Rearrangements In The Complex Chromosomal Aberration Involving 5p152, 2q311, And 18q2132, Zain Dardas, Dana Marafi, Ruizhi Duan, Jawid M Fatih, Omnia F El-Rashidy, Christopher M Grochowski, Claudia M B Carvalho, Shalini N Jhangiani, Weimin Bi, Haowei Du, Richard A Gibbs, Jennifer E Posey, Daniel G Calame, Maha S Zaki, James R Lupski

Faculty, Staff and Students Publications

Despite extensive research into the genetic underpinnings of neurodevelopmental disorders (NDD), many clinical cases remain unresolved. We studied a female proband with a NDD, mildly dysmorphic facial features, and brain stem hypoplasia on neuroimaging. Comprehensive genomic analyses revealed a terminal 5p loss and a terminal 18q gain in the proband while a diploid copy number for chromosomes 5 and 18 in both parents. Genomic investigations in the proband identified an unbalanced translocation t(5;18) with additional genetic material from chromosome 2 (2q31.3) inserted at the breakpoint, pointing to a complex chromosomal rearrangement (CCR) involving 5p15.2, 2q31.3, and 18q21.32. Breakpoint junction analyses …

Characterizing Features Affecting Local Ancestry Inference Performance In Admixed Populations, Jessica Honorato-Mauer, Nirav N Shah, Adam X Maihofer, Clement C Zai, Sintia Belangero, Caroline M Nievergelt, Marcos Santoro, Elizabeth G Atkinson

Faculty, Staff and Students Publications

In recent years, significant efforts have been made to improve methods for genomic studies of admixed populations using local ancestry inference (LAI). Accurate LAI is crucial to ensure that downstream analyses accurately reflect the genetic ancestry of research participants. Here, we test analytic strategies for LAI to provide guidelines for optimal accuracy, focusing on admixed populations reflective of Latin America's primary continental ancestries-African (AFR), Amerindigenous (AMR), and European (EUR). Simulating linkage-disequilibrium-informed admixed haplotypes under a variety of 2- and 3-way admixture models, we implemented a standard LAI pipeline, testing the impact of reference panel composition, DNA data type, demography, and …

Whole Exome Sequencing As A Screening Tool In Dogs: A Pilot Study, Fréderique Boeykens, Evelien Bogaerts, Liesbeth Vossaert, Luc Peelman, Filip Van Nieuwerburgh, Jimmy H Saunders, Bart J G Broeckx

Faculty, Staff and Students Publications

Background: Whole-exome sequencing (WES) is used to selectively sequence all exons of protein-coding genes. WES is considered as a cost-effective and direct approach for identifying phenotype-associated variants in protein-coding regions and is as such situated between the traditional Sanger sequencing and whole genome sequencing (WGS). While WES is already widely used as a clinical tool in human and medical genetics, its use in veterinary medicine is currently restricted to research purposes. In this article, we aimed to provide baseline performance characteristics of a WES design to assess its suitability with future applications in veterinary clinical genetics in mind.

Methods: To …

Characterization And Visualization Of Tandem Repeats At Genome Scale, Egor Dolzhenko, Adam English, Harriet Dashnow, Guilherme De Sena Brandine, Tom Mokveld, William J Rowell, Caitlin Karniski, Zev Kronenberg, Matt C Danzi, Warren A Cheung, Chengpeng Bi, Emily Farrow, Aaron Wenger, Khi Pin Chua, Verónica Martínez-Cerdeño, Trevor D Bartley, Peng Jin, David L Nelson, Stephan Zuchner, Tomi Pastinen, Aaron R Quinlan, Fritz J Sedlazeck, Michael A Eberle

Faculty, Staff and Students Publications

Tandem repeat (TR) variation is associated with gene expression changes and numerous rare monogenic diseases. Although long-read sequencing provides accurate full-length sequences and methylation of TRs, there is still a need for computational methods to profile TRs across the genome. Here we introduce the Tandem Repeat Genotyping Tool (TRGT) and an accompanying TR database. TRGT determines the consensus sequences and methylation levels of specified TRs from PacBio HiFi sequencing data. It also reports reads that support each repeat allele. These reads can be subsequently visualized with a companion TR visualization tool. Assessing 937,122 TRs, TRGT showed a Mendelian concordance of …

Histone Serotonylation Regulates Ependymoma Tumorigenesis, Hsiao-Chi Chen, Peihao He, Malcolm Mcdonald, Michael R Williamson, Srinidhi Varadharajan, Brittney Lozzi, Junsung Woo, Dong-Joo Choi, Debosmita Sardar, Emmet Huang-Hobbs, Hua Sun, Siri M Ippagunta, Antrix Jain, Ganesh Rao, Thomas E Merchant, David W Ellison, Jeffrey L Noebels, Kelsey C Bertrand, Stephen C Mack, Benjamin Deneen

Faculty, Staff and Students Publications

Bidirectional communication between tumors and neurons has emerged as a key facet of the tumor microenvironment that drives malignancy1,2. Another hallmark feature of cancer is epigenomic dysregulation, where alterations in gene expression influences cell states and interactions with the tumor microenvironment3. Ependymoma (EPN) is a pediatric brain tumor that relies on epigenomic remodeling to engender malignancy4,5; how these epigenetic mechanisms intersect with extrinsic neuronal signaling during EPN tumor progression is unknown. Here we show that activity of serotonergic neurons regulates EPN tumorigenesis, while serotonin itself also serves as an activating …

Rna 2′-O-Methylation Promotes Persistent R-Loop Formation And Aid-Mediated Igh Class Switch Recombination, Muzaffer Ahmad Kassab, Yibin Chen, Xin Wang, Bo He, Eric J Brown, Xiaochun Yu

Faculty, Staff and Student Publications

BACKGROUND: RNA-DNA hybrids or R-loops are associated with deleterious genomic instability and protective immunoglobulin class switch recombination (CSR). However, the underlying phenomenon regulating the two contrasting functions of R-loops is unknown. Notably, the underlying mechanism that protects R-loops from classic RNase H-mediated digestion thereby promoting persistence of CSR-associated R-loops during CSR remains elusive.

RESULTS: Here, we report that during CSR, R-loops formed at the immunoglobulin heavy (IgH) chain are modified by ribose 2'-O-methylation (2'-OMe). Moreover, we find that 2'-O-methyltransferase fibrillarin (FBL) interacts with activation-induced cytidine deaminase (AID) associated snoRNA aSNORD1C to facilitate the 2'-OMe. Moreover, deleting AID C-terminal tail impairs …

The Role Of Epigenetic Mechanisms In The Long-Term Effects Of Early-Life Adversity And Mother-Infant Relationship On Physiology And Behavior Of Offspring In Laboratory Rats And Mice, Olga V Burenkova, Elena L Grigorenko

Faculty, Staff and Students Publications

Maternal care during the early postnatal period of altricial mammals is a key factor in the survival and adaptation of offspring to environmental conditions. Natural variations in maternal care and experimental manipulations with maternal-child relationships modeling early-life adversity (ELA) in laboratory rats and mice have a strong long-term influence on the physiology and behavior of offspring in rats and mice. This literature review is devoted to the latest research on the role of epigenetic mechanisms in these effects of ELA and mother-infant relationship, with a focus on the regulation of hypothalamic-pituitary-adrenal axis and brain-derived neurotrophic factor. An important part of …

Fam20a: A Potential Diagnostic Biomarker For Lung Squamous Cell Carcinoma, Yalin Zhang, Qin Sun, Yangbo Liang, Xian Yang, Hailian Wang, Siyuan Song, Yi Wang, Yong Feng

Faculty, Staff and Students Publications

Background: Lung squamous cell carcinoma (LUSC) ranks among the carcinomas with the highest incidence and dismal survival rates, suffering from a lack of effective therapeutic strategies. Consequently, biomarkers facilitating early diagnosis of LUSC could significantly enhance patient survival. This study aims to identify novel biomarkers for LUSC.

Methods: Utilizing the TCGA, GTEx, and CGGA databases, we focused on the gene encoding Family with Sequence Similarity 20, Member A (FAM20A) across various cancers. We then corroborated these bioinformatic predictions with clinical samples. A range of analytical tools, including Kaplan-Meier, MethSurv database, Wilcoxon rank-sum, Kruskal-Wallis tests, Gene Set Enrichment Analysis, …

Methylation Of Nonessential Genes In Cutaneous Melanoma – Rule Out Hypothesis, Ivan P Gorlov, Kathleen Conway, Sharon N Edmiston, Eloise A Parrish, Honglin Hao, Christopher I Amos, Spiridon Tsavachidis, Olga Y Gorlova, Colin Begg, Eva Hernando, Chao Cheng, Ronglai Shen, Irene Orlow, Li Luo, Marc S Ernstoff, Pei Fen Kuan, David W Ollila, Yihsuan S Tsai, Marianne Berwick, Nancy E Thomas

Faculty, Staff and Students Publications

Differential methylation plays an important role in melanoma development and is associated with survival, progression and response to treatment. However, the mechanisms by which methylation promotes melanoma development are poorly understood. The traditional explanation of selective advantage provided by differential methylation postulates that hypermethylation of regulatory 5'-cytosine-phosphate-guanine-3' dinucleotides (CpGs) downregulates the expression of tumor suppressor genes and therefore promotes tumorigenesis. We believe that other (not necessarily alternative) explanations of the selective advantages of methylation are also possible. Here, we hypothesize that melanoma cells use methylation to shut down transcription of nonessential genes - those not required for cell survival and …

High-Throughput Profiling Of Histone Post-Translational Modifications And Chromatin Modifying Proteins By Reverse Phase Protein Array, Xuan Wang, Zhongcheng Shi, Hsin-Yi Lu, Jean J Kim, Wen Bu, Jose A Villalobos, Dimuthu N Perera, Sung Yun Jung, Tao Wang, Sandra L Grimm, Bethany C Taylor, Kimal Rajapakshe, Hyekyung Park, Julia Wulfkuhle, Nicolas L Young, Yi Li, Cristian Coarfa, Dean P Edwards, Shixia Huang

Faculty, Staff and Students Publications

Epigenetic variation plays a significant role in normal development and human diseases including cancer, in part through post-translational modifications (PTMs) of histones. Identification and profiling of changes in histone PTMs, and in proteins regulating PTMs, are crucial to understanding diseases, and for discovery of epigenetic therapeutic agents. In this study, we have adapted and validated an antibody-based reverse phase protein array (RPPA) platform for profiling 20 histone PTMs and expression of 40 proteins that modify histones and other epigenomic regulators. The specificity of the RPPA assay for histone PTMs was validated with synthetic peptides corresponding to histone PTMs and by …

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 …

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 …

Integrating Mouse And Human Genetic Data To Move Beyond Gwas And Identify Causal Genes In Cholesterol Metabolism, Zhonggang Li, James A Votava, Gregory J M Zajac, Jenny N Nguyen, Fernanda B Leyva Jaimes, Sophia M Ly, Jacqueline A Brinkman, Marco De Giorgi, Sushma Kaul, Cara L Green, Samantha L St Clair, Sabrina L Belisle, Julia M Rios, David W Nelson, Mary G Sorci-Thomas, William R Lagor, Dudley W Lamming, Chi-Liang Eric Yen, Brian W Parks

Faculty, Staff and Students Publications

Identifying the causal gene(s) that connects genetic variation to a phenotype is a challenging problem in genome-wide association studies (GWASs). Here, we develop a systematic approach that integrates mouse liver co-expression networks with human lipid GWAS data to identify regulators of cholesterol and lipid metabolism. Through our approach, we identified 48 genes showing replication in mice and associated with plasma lipid traits in humans and six genes on the X chromosome. Among these 54 genes, 25 have no previously identified role in lipid metabolism. Based on functional studies and integration with additional human lipid GWAS datasets, we pinpoint Sestrin1 as …

N-Terminal Domain Of Human Uracil Dna Glycosylase (Hung2) Promotes Targeting To Uracil Sites Adjacent To Ssdna-Dsdna Junctions, Brian P Weiser, Gaddiel Rodriguez, Philip A Cole, James T Stivers

Rowan-Virtua School of Osteopathic Medicine Departmental Research

The N-terminal domain (NTD) of nuclear human uracil DNA glycosylase (hUNG2) assists in targeting hUNG2 to replication forks through specific interactions with replication protein A (RPA). Here, we explored hUNG2 activity in the presence and absence of RPA using substrates with ssDNA-dsDNA junctions that mimic structural features of the replication fork and transcriptional R-loops. We find that when RPA is tightly bound to the ssDNA overhang of junction DNA substrates, base excision by hUNG2 is strongly biased toward uracils located 21 bp or less from the ssDNA-dsDNA junction. In the absence of RPA, hUNG2 still showed an 8-fold excision bias …

Mechanism Of Transcription Anti-Termination In Human Mitochondria., Hauke S Hillen, Andrey V Parshin, Karen Agaronyan, Yaroslav I Morozov, James J Graber, Aleksandar Chernev, Kathrin Schwinghammer, Henning Urlaub, Michael Anikin, Patrick Cramer, Dmitry Temiakov

Rowan-Virtua School of Osteopathic Medicine Departmental Research

In human mitochondria, transcription termination events at a G-quadruplex region near the replication origin are thought to drive replication of mtDNA by generation of an RNA primer. This process is suppressed by a key regulator of mtDNA-the transcription factor TEFM. We determined the structure of an anti-termination complex in which TEFM is bound to transcribing mtRNAP. The structure reveals interactions of the dimeric pseudonuclease core of TEFM with mobile structural elements in mtRNAP and the nucleic acid components of the elongation complex (EC). Binding of TEFM to the DNA forms a downstream "sliding clamp," providing high processivity to the EC. …

Aging And Environmental Exposures Alter Tissue-Specific Dna Methylation Dependent Upon Cpg Island Context, Brock C. Christensen, E Andres Houseman, Carmen J. Marsit, Shichun Zheng, Margaret R. Wrensch, Joseph L. Wiemels, Heather H. Nelson, Margaret R. Karagas

Dartmouth Scholarship

Epigenetic control of gene transcription is critical for normal human development and cellular differentiation. While alterations of epigenetic marks such as DNA methylation have been linked to cancers and many other human diseases, interindividual epigenetic variations in normal tissues due to aging, environmental factors, or innate susceptibility are poorly characterized. The plasticity, tissue-specific nature, and variability of gene expression are related to epigenomic states that vary across individuals. Thus, population-based investigations are needed to further our understanding of the fundamental dynamics of normal individual epigenomes. We analyzed 217 non-pathologic human tissues from 10 anatomic sites at 1,413 autosomal CpG loci …