Genetic Processes Commons^™

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 …

Ion-Dna Interactions As A Key Determinant Of Uracil Dna Glycosylase Activity., Sharon N Greenwood, Alexis N Dispensa, Matthew Wang, Justin R Bauer, Timothy D Vaden, Zhiwei Liu, Brian P Weiser

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Because of their ubiquitous presence, ions interact with numerous macromolecules in the cell and affect critical biological processes. Here, we discuss how cations including Mg²⁺ alter the enzymatic activity of a DNA glycosylase by tuning its affinity for DNA. The response of uracil DNA glycosylase (UNG2) to Mg²⁺ ions in solution is biphasic and paradoxical, where low concentrations of the ion stimulate the enzyme, but high concentrations inhibit the enzyme. We analyzed this phenomenon by modeling experimental data with a statistical framework that we empirically derived to understand molecular systems that display biphasic behaviors. Parameters from our statistical …

Heredity, Chris Burley, Lisa K. Lashley, Charles J. Golden

Essays in Developmental Psychology

Heredity is the sum of biological processes that result in the transmission of genetic traits from parents to their offspring, making each individual unique. Through the transmission of genetic traits, heredity is responsible for each individual’s genotype, as well as his or her phenotype. The genes that are passed down from generation to generation have a considerable influence on psychological characteristics including intelligence, personality, mental health, and patterns of behavior. However, when considering psychological characteristics passed down through heredity, it is vital that environmental aspects are also considered.

Closing The Gaps, And Improving Somatic Structural Variant Analysis And Benchmarking Using Chm13-T2t, Luis F Paulin, Jeremy Fan, Kieran O'Neill, Erin Pleasance, Vanessa L Porter, Steven J M Jones, Fritz J Sedlazeck

Faculty, Staff and Students Publications

The complexities of cancer genomes are becoming more easily interpreted due to advancements in sequencing technologies and improved bioinformatic analysis. Structural variants (SVs) represent an important subset of somatic events in tumors. While the detection of SVs has been markedly improved by the development of long-read sequencing, somatic variant identification and annotation remain challenging. We hypothesized that the use of a completed human reference genome (CHM13-T2T) would improve somatic SV calling. Our findings in a tumor-normal matched benchmark sample and three patient samples show that the CHM13-T2T improves SV detection accuracy compared to GRCh38 with a notable reduction in false-positive …

A Hitchhiker’S Guide To Long-Read Genomic Analysis, Medhat Mahmoud, Daniel P Agustinho, Fritz J Sedlazeck

Faculty, Staff and Students Publications

Over the past decade, long-read sequencing has evolved into a pivotal technology for uncovering the hidden and complex regions of the genome. Significant cost efficiency, scalability, and accuracy advancements have driven this evolution. Concurrently, novel analytical methods have emerged to harness the full potential of long reads. These advancements have enabled milestones such as the first fully completed human genome, enhanced identification and understanding of complex genomic variants, and deeper insights into the interplay between epigenetics and genomic variation. This mini-review provides a comprehensive overview of the latest developments in long-read DNA sequencing analysis, encompassing reference-based and de novo assembly …

Unraveling The Hidden Complexity Of Cancer Through Long-Read Sequencing, Qiuhui Li, Ayse G Keskus, Justin Wagner, Michal B Izydorczyk, Winston Timp, Fritz J Sedlazeck, Alison P Klein, Justin M Zook, Mikhail Kolmogorov, Michael C Schatz

Faculty, Staff and Students Publications

Cancer is fundamentally a disease of the genome, characterized by extensive genomic, transcriptomic, and epigenomic alterations. Most current studies predominantly use short-read sequencing, gene panels, or microarrays to explore these alterations; however, these technologies can systematically miss or misrepresent certain types of alterations, especially structural variants, complex rearrangements, and alterations within repetitive regions. Long-read sequencing is rapidly emerging as a transformative technology for cancer research by providing a comprehensive view across the genome, transcriptome, and epigenome, including the ability to detect alterations that previous technologies have overlooked. In this Perspective, we explore the current applications of long-read sequencing for both …

K-Mer Analysis Of Long-Read Alignment Pileups For Structural Variant Genotyping, Adam C English, Fabio Cunial, Ginger A Metcalf, Richard A Gibbs, Fritz J Sedlazeck

Faculty, Staff and Students Publications

Accurately genotyping structural variant (SV) alleles is crucial to genomics research. We present a novel method (kanpig) for genotyping SVs that leverages variant graphs and k-mer vectors to rapidly generate accurate SV genotypes. Benchmarking against the latest SV datasets shows kanpig achieves a single-sample genotyping concordance of 82.1%, significantly outperforming existing tools, which average 66.3%. We explore kanpig's use for multi-sample projects by testing on 47 genetically diverse samples and find kanpig accurately genotypes complex loci (e.g. SVs neighboring other SVs), and produces higher genotyping concordance than other tools. Kanpig requires only 43 seconds to process a single sample's 20x …

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 …

The Icf Syndrome Protein Cdca7 Harbors A Unique Dna Binding Domain That Recognizes A Cpg Dyad In The Context Of A Non-B Dna, Swanand Hardikar, Ren Ren, Zhengzhou Ying, Jujun Zhou, John R Horton, Matthew D Bramble, Bin Liu, Yue Lu, Bigang Liu, Luis Della Coletta, Jianjun Shen, Jiameng Dan, Xing Zhang, Xiaodong Cheng, Taiping Chen

Faculty, Staff and Student Publications

CDCA7, encoding a protein with a carboxyl-terminal cysteine-rich domain (CRD), is mutated in immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome, a disease related to hypomethylation of juxtacentromeric satellite DNA. How CDCA7 directs DNA methylation to juxtacentromeric regions is unknown. Here, we show that the CDCA7 CRD adopts a unique zinc-binding structure that recognizes a CpG dyad in a non-B DNA formed by two sequence motifs. CDCA7, but not ICF mutants, preferentially binds the non-B DNA with strand-specific CpG hemi-methylation. The unmethylated sequence motif is highly enriched at centromeres of human chromosomes, whereas the methylated motif is distributed throughout …

Unveiling Microbial Diversity: Harnessing Long-Read Sequencing Technology, Daniel P Agustinho, Yilei Fu, Vipin K Menon, Ginger A Metcalf, Todd J Treangen, Fritz J Sedlazeck

Faculty, Staff and Students Publications

Long-read sequencing has recently transformed metagenomics, enhancing strain-level pathogen characterization, enabling accurate and complete metagenome-assembled genomes, and improving microbiome taxonomic classification and profiling. These advancements are not only due to improvements in sequencing accuracy, but also happening across rapidly changing analysis methods. In this Review, we explore long-read sequencing's profound impact on metagenomics, focusing on computational pipelines for genome assembly, taxonomic characterization and variant detection, to summarize recent advancements in the field and provide an overview of available analytical methods to fully leverage long reads. We provide insights into the advantages and disadvantages of long reads over short reads and …

Grb2 Stabilizes Rad51 At Reversed Replication Forks Suppressing Genomic Instability And Innate Immunity Against Cancer, Zu Ye, Shengfeng Xu, Yin Shi, Xueqian Cheng, Yuan Zhang, Sunetra Roy, Sarita Namjoshi, Michael A Longo, Todd M Link, Katharina Schlacher, Guang Peng, Dihua Yu, Bin Wang, John A Tainer, Zamal Ahmed

Faculty, Staff and Student Publications

Growth factor receptor-bound protein 2 (GRB2) is a cytoplasmic adapter for tyrosine kinase signaling and a nuclear adapter for homology-directed-DNA repair. Here we find nuclear GRB2 protects DNA at stalled replication forks from MRE11-mediated degradation in the BRCA2 replication fork protection axis. Mechanistically, GRB2 binds and inhibits RAD51 ATPase activity to stabilize RAD51 on stalled replication forks. In GRB2-depleted cells, PARP inhibitor (PARPi) treatment releases DNA fragments from stalled forks into the cytoplasm that activate the cGAS-STING pathway to trigger pro-inflammatory cytokine production. Moreover in a syngeneic mouse metastatic ovarian cancer model, GRB2 depletion in the context of PARPi treatment …

Multiple Unfolded Protein Response Pathways Cooperate To Link Cytosolic Dsdna Release To Stimulator Of Interferon Gene Activation, Tiancheng Hu, Yiping Liu, Jeremy Fleck, Cason King, Elaine Schalk, Zhenyu Zhang, Andrew Mehle, Judith A Smith

Faculty, Staff and Student Publications

The double-stranded DNA (dsDNA) sensor STING has been increasingly implicated in responses to "sterile" endogenous threats and pathogens without nominal DNA or cyclic di-nucleotide stimuli. Previous work showed an endoplasmic reticulum (ER) stress response, known as the unfolded protein response (UPR), activates STING. Herein, we sought to determine if ER stress generated a STING ligand, and to identify the UPR pathways involved. Induction of IFN-β expression following stimulation with the UPR inducer thapsigargin (TPG) or oxygen glucose deprivation required both STING and the dsDNA-sensing cyclic GMP-AMP synthase (cGAS). Furthermore, TPG increased cytosolic mitochondrial DNA, and immunofluorescence visualized dsDNA punctae in …

Pathogen-Driven Crispr Screens Identify Trex1as A Regulator Of Dna Self-Sensing During Influenza Virus Infection, Cason R King, Yiping Liu, Katherine A Amato, Grace A Schaack, Clayton Mickelson, Autumn E Sanders, Tony Hu, Srishti Gupta, Ryan A Langlois, Judith A Smith, Andrew Mehle

Faculty, Staff and Student Publications

Host:pathogen interactions dictate the outcome of infection, yet the limitations of current approaches leave large regions of this interface unexplored. Here, we develop a novel fitness-based screen that queries factors important during the middle to late stages of infection. This is achieved by engineering influenza virus to direct the screen by programming dCas9 to modulate host gene expression. Our genome-wide screen for pro-viral factors identifies the cytoplasmic DNA exonuclease TREX1. TREX1 degrades cytoplasmic DNA to prevent inappropriate innate immune activation by self-DNA. We reveal that this same process aids influenza virus replication. Infection triggers release of mitochondrial DNA into the …

Parp1 Associates With R-Loops To Promote Their Resolution And Genome Stability, Natalie Laspata, Parminder Kaur, Sofiane Yacine Mersaoui, Daniela Muoio, Zhiyan Silvia Liu, Maxwell Henry Bannister, Hai Dang Nguyen, Caroline Curry, John M. Pascal, Guy G. Poirier, Hong Wang, Jean-Yves Masson, Elise Fouquerel

Student Papers, Posters & Projects

PARP1 is a DNA-dependent ADP-Ribose transferase with ADP-ribosylation activity that is triggered by DNA breaks and non-B DNA structures to mediate their resolution. PARP1 was also recently identified as a component of the R-loop-associated protein-protein interaction network, suggesting a potential role for PARP1 in resolving this structure. R-loops are three-stranded nucleic acid structures that consist of a RNA-DNA hybrid and a displaced non-template DNA strand. R-loops are involved in crucial physiological processes but can also be a source of genome instability if persistently unresolved. In this study, we demonstrate that PARP1 binds R-loops in vitro and associates with R-loop formation …

Discovery Of Highly Potent And Bmpr2-Selective Kinase Inhibitors Using Dna-Encoded Chemical Library Screening, Ram K Modukuri, Diana Monsivais, Feng Li, Murugesan Palaniappan, Kurt M Bohren, Zhi Tan, Angela F Ku, Yong Wang, Chandrashekhar Madasu, Jian-Yuan Li, Suni Tang, Gabriella Miklossy, Stephen S Palmer, Damian W Young, Martin M Matzuk

Faculty, Staff and Students Publications

The discovery of monokinase-selective inhibitors for patients is challenging because the 500+ kinases encoded by the human genome share highly conserved catalytic domains. Until now, no selective inhibitors unique for a single transforming growth factor β (TGFβ) family transmembrane receptor kinase, including bone morphogenetic protein receptor type 2 (BMPR2), have been reported. This dearth of receptor-specific kinase inhibitors hinders therapeutic options for skeletal defects and cancer as a result of an overactivated BMP signaling pathway. By screening 4.17 billion “unbiased” and “kinase-biased” DNA-encoded chemical library molecules, we identified hits CDD-1115 and CDD-1431, respectively, that were low-nanomolar selective kinase inhibitors of …

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 …

Curated Variation Benchmarks For Challenging Medically Relevant Autosomal Genes, Justin Wagner, Nathan D Olson, Lindsay Harris, Jennifer Mcdaniel, Haoyu Cheng, Arkarachai Fungtammasan, Yih-Chii Hwang, Richa Gupta, Aaron M Wenger, William J Rowell, Ziad M Khan, Jesse Farek, Yiming Zhu, Aishwarya Pisupati, Medhat Mahmoud, Chunlin Xiao, Byunggil Yoo, Sayed Mohammad Ebrahim Sahraeian, Danny E Miller, David Jáspez, José M Lorenzo-Salazar, Adrián Muñoz-Barrera, Luis A Rubio-Rodríguez, Carlos Flores, Giuseppe Narzisi, Uday Shanker Evani, Wayne E Clarke, Joyce Lee, Christopher E Mason, Stephen E Lincoln, Karen H Miga, Mark T W Ebbert, Alaina Shumate, Heng Li, Chen-Shan Chin, Justin M Zook, Fritz J Sedlazeck

Faculty, Staff and Students Publications

The repetitive nature and complexity of some medically relevant genes poses a challenge for their accurate analysis in a clinical setting. The Genome in a Bottle Consortium has provided variant benchmark sets, but these exclude nearly 400 medically relevant genes due to their repetitiveness or polymorphic complexity. Here, we characterize 273 of these 395 challenging autosomal genes using a haplotype-resolved whole-genome assembly. This curated benchmark reports over 17,000 single-nucleotide variations, 3,600 insertions and deletions and 200 structural variations each for human genome reference GRCh37 and GRCh38 across HG002. We show that false duplications in either GRCh37 or GRCh38 result 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 …

Replication Protein A (Rpa) Targeting Of Uracil Dna Glycosylase (Ung2), Derek Chen, Brian P Weiser

Rowan-Virtua Research Day

Replication Protein A (RPA) is a single stranded DNA binding protein which stabilizes ssDNA for replication and repair. One function of RPA is to bind the DNA repair enzyme uracil DNA glycosylase (UNG2) and direct its activity towards ssDNA dsDNA junctions.

UNG2 removes uracil bases from DNA which can appear through dUMP misincorporation or through cytosine deamination. If uracil is present instead of a cytosine, then the original GC pair becomes a GU pair. The uracil will then base pair to adenine in the replicated daughter strand. This results in a GC → AT mutation that could contribute to cancer …

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. …