Biochemistry, Biophysics, and Structural Biology Commons^™

Molecular And Structural Basis For Replication Initiation And Strand Separation By Human Mitochondrial Dna Polymerase Γ, Viktoriia Sokolova, Gina Buchel, S. Strock, Ashok R. Nayak, Dmitry Temiakov

Department of Biochemistry and Molecular Biology Faculty Papers

Defects in human mitochondrial DNA (mtDNA) replication can lead to somatic mutations associated with a range of devastating mitochondrial diseases. However, the molecular mechanisms governing the earliest steps of mtDNA replication and their fidelity remain poorly understood. Here, we found that DNA polymerase gamma (Polγ) forms stable complexes with RNA-DNA primer-template substrates, exhibiting greater stability and lower misincorporation than on DNA-primed substrates. Structural analysis revealed that Polγ interacts with the 2'-OH groups of ribose within the first four nucleotides of the primer, explaining the stability of complexes that utilize RNA primers. Although Polγ requires TWINKLE to extend RNA primers, its …

Three-Dimensional Chromatin Architecture Is Rapidly Restored After Dna Replication, Tyler K. Fenstermaker, Svetlana Petruk, Alexander Mazo

Department of Biochemistry and Molecular Biology Faculty Papers

Studies of post-replicative chromatin exclusively focus on the kinetics of protein binding after DNA replication to understand maintenance of transcriptional programs. Here we investigated both chromatin-bound factors and the three-dimensional architecture of the post-replicative genome in human cells. We found that transcription factors and chromatin looping proteins rapidly associate with nascent DNA. We discovered that the architectural factors, CTCF and YY1, bind to their target sequences immediately following DNA replication, and that chromatin loops from 39 to 425 kb re-form within 10 min of DNA replication. This suggests that the 3D structure of chromatin is at most briefly disrupted by …

Characterization Of Mettl3/14-Mediated M6a Modification In Human Transcriptome Using Nanopore Direct Rna Sequencing, Emily Kurtyan, Andrew J. Stein, Kelly J. Abdalla, Zhangerjiao Yuan, Miten Jain, Fadia Ibrahim

Department of Biochemistry and Molecular Biology Faculty Papers

Post-transcriptional RNA modifications modulate diverse aspects of RNA metabolism. N6-methyladenosine (m6A), one of the most abundant internal RNA modifications, is deposited by the core methyltransferase complex, METTL3 and METTL14. Oxford Nanopore Technologies (ONT) platform permits direct, single RNA molecule sequencing while preserving native modifications. However, without rigorous benchmarking, the accuracy and reproducibility of modification detection remain uncertain. Here, we leveraged ONT to comprehensively profile bona fide m6A modifications in cellular RNAs at single-nucleotide resolution by integrating two direct RNA sequencing chemistries (RNA002 and RNA004) with the m6Anet and Dorado modification-detection models. We independently depleted METTL3 and METTL14 in human cells …

Biophysical Insights Into A Cryptic Ligand Site In The Hydrophobic Core Of Human Pcna, Alexis N. Dispensa, Sharon N, Greenwood, Jason Yang, Daniel E. Logatto, James Fusco, E. Railey White, Roderic G. Eckenhoff, Zhiwei Liu, Brian P. Weiser

Department of Anesthesiology Faculty Papers

Proteins contain small pockets that form due to imperfections in residue packing or the rotational and conformational movement of amino acids. In this work, we used the fluorescent probe 1-aminoanthracene (AMA) to detect a small ligand pocket in the hydrophobic core of human proliferating cell nuclear antigen (PCNA), which is a critical protein for DNA replication and repair. Fluorescence measurements of AMA reported that the core of PCNA had a dielectric constant (ε) of 4, which was very apolar and similar to cyclohexane (ε = 2). Protein mutagenesis, photoaffinity labeling, and molecular dynamics simulations localized the binding site for AMA …

Rna G-Quadruplexes Function As A Tunable Switch Of Fus Phase Separation, Jenny L. Carey, Miyuki Hayashi, Emily A. Welebob, Laura R. Ganser, Huan Wang, Kerry Buckhaults, Jacquelyn A. Depierro, Zheng Shi, James Shorter, Sua Myong, Aaron R. Haeusler, Lin Guo

Department of Biochemistry and Molecular Biology Faculty Papers

Fused in sarcoma (FUS) undergoes liquid-liquid phase separation (LLPS) to support essential cellular functions, but aberrant phase transitions promote toxic aggregation in neurodegenerative disease. Short RNA oligonucleotides can reverse this behavior, yet the structural determinants that govern RNA activity remain poorly defined. Here, we identify RNA G-quadruplexes (rG4s) as tunable structural motifs that potently modulate FUS LLPS. rG4 activity depends on its concentration and is modulated by rG4 length and stability: increasing repeat number switches rG4s from inhibitor to nucleator of FUS assembly, whereas chemical modifications that stabilize rG4 enhance inhibitory function and render these activities resilient to ionic perturbation. …

High Mobility Group Motif Proteins’ Role In Fibrosis, Inflammation, And Vascular Injury In Systemic Sclerosis, Fabian A. Mendoza, Sonsoles Piera-Velazquez, Sergio A. Jimenez

Jefferson Institute of Molecular Medicine Papers and Presentations

Systemic Sclerosis (SSc) is an idiopathic systemic autoimmune disease characterized by progressive cutaneous and systemic fibrosis, severe vasculopathy, and multiple humoral and cellular immunological alterations. The pathogenesis of SSc is highly complex and remains incompletely elucidated. The fibrotic process is a crucial component of SSc and is responsible for organ failure and high mortality. Although an increasing understanding of the fibrotic process has enabled the clinical development of antifibrotic therapeutic agents, these agents have limited clinical efficacy. Recently, the potential role of a group of transcription factors containing a High Mobility Group (HMG) motif, in the development and pathological manifestations …

Mitochondrial Dna Replication Is Regulated By Endoplasmic Reticulum-Mitochondrial Contact Sites, The Mitochondrial Calcium Uniporter, And Manganese, Amaia Lopez De Arbina, Angelica Zamudio-Ochoa, Mikel Muñoz-Oreja, Diego Perez-Rodriguez, Laura Mosqueira-Martín, Rebecca Lasalandra, Marina Villar-Fernandez, Uxoa Fernandez-Pelayo, Laura Rodriguez-Gomez, Seungtae Lee, Francisco Gil-Bea, Nerea Osinalde, Ainara Vallejo-Illaramendi, Dmitry Temiakov, Antonella Spinazzola, Ian Holt

Department of Biochemistry and Molecular Biology Faculty Papers

Mitochondrial DNA replication occurs at contact sites between the endoplasmic reticulum (ER) and mitochondria (ERMCS). Beyond the known role of the tubular ER protein RTN4, the factors regulating this process are poorly defined. Here, we show that repressing the ER protein ERLIN2 in human fibroblasts depletes ER-mitochondrial contact sites and inhibits mitochondrial DNA replication, as does silencing RTN4 or the ER-mitochondrial tether GRP75. GRP75 or RTN4 scarcity also decreases the level of the mitochondrial calcium uniporter (MCU), whose inhibition blocks mitochondrial DNA synthesis. Because ERMCS depletion did not diminish mitochondrial calcium, and MCU complex can transport manganese, we tested whether …

Polθ Activity Modulates Sensitivity To Standard Therapies In Dnmt3a-Deficient Leukemia, Bac Viet Le, Umeshkumar Vekariya, Monika M. Toma, Margaret Nieborowska-Skorska, Marie-Christine Caron, Malgorzata Gozdecka, Zayd Haydar, Martin Walsh, Jayashri Ghosh, Elaine Vaughan-Williams, Paulina Podszywalow-Bartnicka, Anna-Mariya Kukuyan, Sylwia Ziolkowska, Jessica Atkins, Emir Hadzijusufovic, Gurushankar Chandramouly, Reza Nejati, Katarzyna Piwocka, Richard T. Pomerantz, George S. Vassiliou, Brian J.P. Huntly, Peter Valent, Mariusz Wasik, Alfonso Bellacosa, Jean-Yves Masson, Gaorav P. Gupta, Grant A. Challen, Tomasz Skorski

Department of Biochemistry and Molecular Biology Faculty Papers

Myeloid malignancies carrying somatic DNMT3A mutations (DNMT3Amut) are refractory to standard therapy. DNMT3Amut leukemia cells accumulate toxic DNA double-strand breaks (DSBs) and stalled replication forks, rendering them dependent on DNA damage response (DDR). We report here that DNA polymerase theta (Polθ), a key element in DSB repair by end-joining (Polθ-mediated end-joining [TMEJ]) and in fork restarting, promotes survival and proliferation of DNMT3Amut leukemia cells. Polθ is overexpressed in DNMT3Amut leukemia cells due to abrogation of PARP1 PARylation-dependent UBE2O E3 ligase-mediated ubiquitination and proteasomal degradation of Polθ. In addition, PARP1-mediated recruitment of the SMARCAD1-MSH2/MSH3 repressive complex to DSBs is diminished in …

Defining Rna Oligonucleotides That Reverse Deleterious Phase Transitions Of Rna-Binding Proteins With Prion-Like Domains., Lin Guo, Jacob Mann, Jocelyn Mauna, Katie Copley, Hejia Wang, Jack Rubien, Cristian Bergmann, Jenny Carey, Jessica Merjane, Marilyn Ngo, Jiazhen Xu, Hana Odeh, Jiabei Lin, Bo Lim Lee, Laura Ganser, Emma Robinson, Kevin Kim, Anastasia Murthy, Tapas Paul, Bede Portz, Amanda Gleixner, Zamia Diaz, Ashleigh Smirnov, George Padilla, Ellen Lavorando, Carolann Espy, Yulei Shang, Eric Huang, Alessandra Chesi, Nicolas Fawzi, Sua Myong, Christopher Donnelly, James Shorter

Department of Biochemistry and Molecular Biology Faculty Papers

RNA-binding proteins (RBPs) with prion-like domains (PrLDs), such as FUS and TDP-43, condense into functional liquids, which can transform into pathological fibrils that underpin fatal neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD). Here, we define short RNAs that prevent FUS fibrillization by promoting liquid phases and distinct short RNAs that prevent and reverse FUS condensation and fibrillization. These activities require interactions with multiple RNA-binding domains of FUS and are encoded by RNA sequence, length, and structure. We define a short RNA that dissolves cytoplasmic FUS aggregates, restores nuclear FUS, and mitigates FUS toxicity in optogenetic models and ALS …

Structural Basis Of Panx1 Permeation And Positive Modulation By Mefloquine, Yangyang Li, Zheng Ruan, Junuk Lee, Ian Orozco, Edward Zhou, Juan Du, Wei Lü

Department of Biochemistry and Molecular Biology Faculty Papers

Purinergic signaling relies on ATP release through exocytosis and large-pore channels. Large-pore channels permeate both small anions like chloride and large signaling molecules like ATP, but how this broad cargo selectivity is structurally controlled remains elusive. Here we investigate PANX1, a prototypical large-pore channel, and uncover structural plasticity at the extracellular entrance formed by seven tryptophan (W74) residues. The W74 sidechains are flexible, sampling conformations that range from a constricted state permissive only to chloride to a dilated state compatible with ATP. These states are coupled to variable cation-π interactions between W74 and arginine 75 (R75), suggesting a mechanism for …

Dna Extrusion Size Determines Pathway Choice During Cag Repeat Expansion, Mayuri Bhatia, Ashutosh S. Phadte, Anna Lakhina, Anthony R. Monte Carloi Iii, Sarah Barndt, Anna Pluciennik

Department of Biochemistry and Molecular Biology Faculty Papers

DNA triplet repeat expansion causes several primarly neurological disorders like Huntington's disease, myotonic dystrophy type 1, and fragile-X related disorders. There is general consensus that recognition of extrahelical extrusions or hairpin-loop structures (formed by strand slippage) by the DNA mismatch repair protein MutSβ leads to repeat expansion by a mutagenic process. By contrast, the FAN1 nuclease attenuates triplet repeat expansion, the molecular basis of which was explained by our recent finding that FAN1 nuclease cleaves and initiates removal of extrahelical extrusions. Here we show that extrusions containing two or more triplet repeats are subject to recognition and processing by either …

Targeting The Bcl2 Family: Advances And Challenges In Bh3 Mimetic-Based Therapies, Nabanita Mukherjee, James Sheetz, Yiqun Shellman

Student Papers, Posters & Projects

The BCL2 family of proteins plays a pivotal role in regulating apoptosis and cellular homeostasis, making them critical therapeutic targets in cancer and other diseases characterized by pathological cell survival. BH3 mimetics, small molecules that selectively inhibit anti-apoptotic BCL2 family members, have achieved significant clinical success, particularly in hematologic malignancies. However, several challenges remain, including resistance mechanisms, toxicity (such as MCL1 inhibitor-associated cardiotoxicity), and the intricate balance between apoptotic and non-apoptotic functions. This review provides a comprehensive overview of BCL2 family biology, the development and clinical application and outcomes of BH3 mimetics, and the emerging resistance mechanism known as double-bolt …

Development Of Emerin Mrna Lipid Nanoparticles To Rescue Myogenic Differentiation., Nicholas Marano, Liza Elif Guner, Rachel S Riley, James M Holaska

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Emery-Dreifuss muscular dystrophy 1 (EDMD1) arises from mutations in EMD. Most EDMD1 patients lack detectable emerin expression. They experience symptoms such as skeletal muscle wasting, joint contractures, and cardiac conduction defects. Currently, physicians rely on treating patient symptoms without addressing the underlying cause-lack of functional emerin protein. Thus, there is a need for therapeutic approaches that restore emerin protein expression to improve patient outcomes. One way would be to deliver emerin mRNA or protein directly to affected tissues to restore tissue homeostasis. Here, we evaluated the utility of lipid nanoparticles (LNPs) to deliver emerin mRNA to diseased cells. LNPs …

Identification Of Serum Exosome Proteins In Systemic Sclerosis With Interstitial Lung Disease By Aptamer Proteomics, Sonsoles Piera-Velazquez, Simon T. Dillon, Xuesong Gu, Towia A. Libermann, Sergio A. Jimenez

Jefferson Institute of Molecular Medicine Papers and Presentations

OBJECTIVE: A major unmet need for Systemic Sclerosis (SSc) clinical management is the absence of well validated biomarkers for early diagnosis of SSc-associated interstitial lung disease (SSc-ILD). The objective of this study was to identify proteins contained within serum exosomes that may serve as potential biomarkers to differentiate patients with Diffuse SSc without SSc-ILD from patients with Diffuse SSc with SSc-ILD employing aptamer-based proteomics.

METHODS: Serum exosomes were isolated from two cohorts of patients. The first cohort included 15 patients with Diffuse SSc without SSc-ILD and 14 patients with Diffuse SSc with SSc-ILD and the second cohort included 12 patients …

A Hormone-Dependent Trna Half Promotes Cell Cycle Progression Via Destabilization Of P21 Mrna, Takuya Kawamura, Megumi Shigematsu, Yohei Kirino

Department of Biochemistry and Molecular Biology Faculty Papers

tRNA halves are among the most abundant short non-coding RNAs in the cellular transcriptome. Here we report that in androgen receptor-positive LNCaP prostate cancer cells, the hormone-dependent 5'-tRNALysCUU half promoted cell proliferation by facilitating cell cycle progression. Global mRNA profiling upon the 5'-tRNALysCUU half depletion revealed that the mRNA of p21, a negative regulator of the cell cycle, is post-transcriptionally destabilized via a 5'-tRNALysCUU half-driven mechanism. YBX1, identified as a protein interacting with 5'-tRNALysCUU half in the cytosol, was shown to stabilize p21 mRNA. Specific sequences resembling the 5'-tRNALysCUU half, located in the 3'-UTR of p21 mRNA and termed LL588, …

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 …

Molecular Subtyping Of Hypertensive Disorders Of Pregnancy, Michal Elovitz, Elaine Gee, Nathaniel Delaney-Busch, Alison Moe, Mitsu Reddy, Arkady Khodursky, Johnny La, Ilma Abbas, Kay Mekaru, Hunter Collins, Farooq Siddiqui, Rory Nolan, Rupsa Boelig, Daniel Kiefer, Pamela Simmons, George Saade, Antonio Saad, Ebony Carter, Thomas Mcelrath, Stephen Quake, Mark Depristo, Carrie Haverty, Manfred Lee, Eugeni Namsaraev, Vincenzo Berghella, Ai-Ris Collier, Antonia Frolova, Esther Park-Hwang, Luis Pacheco, Elizabeth Sutton, Maneesh Jain, Kara Rood, William A Grobman, Joseph Biggio, Cynthia Gyamfi-Bannerman, Arun Jeyabalan, Morten Rasmussen

Department of Obstetrics and Gynecology Faculty Papers

Hypertensive disorders of pregnancy (HDP), including preeclampsia, affect 1 in 6 pregnancies, are major contributors to maternal morbidity and mortality, yet lack precision medicine strategies. Analyzing transcriptomic data from a prospectively-collected diverse cohort (n = 9102), this study reveals distinct RNA subtypes in maternal blood, reclassifying clinical HDP phenotypes like early/late-onset preeclampsia. The placental gene PAPPA2 strongly predicts the most severe forms of preeclampsia in individuals without pre-existing high risk factors, months before symptoms, and its overexpression correlates with earlier delivery in a dose-dependent manner. Further, molecular subtypes characterized by immune genes are upregulated in less severe forms of HDP. …

Genome-Wide Profiling Of Trna Modifications By Induro-Trnaseq Reveals Coordinated Changes, Yuko Nakano, Howard Gamper, Henri Mcguigan, Sunita Maharjan, Jiatong Li, Zhiyi Sun, Erbay Yigit, Sebastian Grünberg, Keerthana Krishnan, Nan-Sheng Li, Joseph Piccirilli, Ralph Kleiner, Nicole Nichols, Brian Gregory, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

While all native tRNAs undergo extensive post-transcriptional modifications as a mechanism to regulate gene expression, mapping these modifications remains challenging. The critical barrier is the difficulty of readthrough of modifications by reverse transcriptases (RTs). Here we use Induro-a new group-II intron-encoded RT-to map and quantify genome-wide tRNA modifications in Induro-tRNAseq. We show that Induro progressively increases readthrough over time by selectively overcoming RT stops without altering the misincorporation frequency. In a parallel analysis of Induro vs. a related RT, we provide comparative datasets to facilitate the prediction of each modification. We assess tRNA modifications across five human cell lines and …

Structure And Mechanism Of Biosynthesis Of Streptococcus Mutans Cell Wall Polysaccharide., Jeffrey S. Rush, Svetlana Zamakhaeva, Nicholas R Murner, Pan Deng, Andrew J Morris, Cameron W Kenner, Ian Black, Christian Heiss, Parastoo Azadi, Konstantin V Korotkov, Göran Widmalm, Natalia Korotkova

Molecular and Cellular Biochemistry Faculty Publications

Streptococcus mutans, the causative agent of human dental caries, expresses a cell wall attached Serotype c-specific Carbohydrate (SCC) that is critical for cell viability. SCC consists of a polyrhamnose backbone of →3)α-Rha(1 → 2)α-Rha(1→ repeats with glucose (Glc) side-chains and glycerol phosphate (GroP) decorations. This study reveals that SCC has one predominant and two more minor Glc modifications. The predominant Glc modification, α-Glc, attached to position 2 of 3-rhamnose, is installed by SccN and SccM glycosyltransferases and is the site of the GroP addition. The minor Glc modifications are β-Glc linked to position 4 of 3-rhamnose installed by SccP and …

Nls-Binding Deficient Kapβ2 Reduces Neurotoxicity Via Selective Interaction With C9orf72-Als/Ftd Dipeptide Repeats, Kevin Kim, Amandeep Girdhar, Maria Elena Cicardi, V. Kankate, Miyuki Hayashi, Ruoyu Yang, Jenny Carey, Charlotte M Fare, James Shorter, Gino Cingolani, Davide Trotti, Lin Guo

Department of Biochemistry and Molecular Biology Faculty Papers

Arginine-rich dipeptide repeat proteins (R-DPRs) are highly toxic proteins found in patients with C9orf72-linked amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). R-DPRs can cause toxicity by disrupting the natural phase behavior of RNA-binding proteins (RBPs). Mitigating this abnormal phase behavior is, therefore, crucial to reduce R-DPR-induced toxicity. Here, we use FUS as a model RBP to investigate the mechanism of R-DPR-induced aberrant RBP phase transition. We find that this phase transition can be mitigated by Kapβ2. However, as a nuclear import receptor and phase modifier for PY-NLS-containing RBPs, the function of WT Kapβ2 could lead to undesired interaction with its …

The Importance Of Solution Studies For The Structural Characterization Of The Enterovirus 5' Cloverleaf, Morgan G. Daniels, Meagan E. Werner, Xiaobing Zuo, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

Enteroviruses initiate genomic replication via a highly conserved mechanism that is controlled by an RNA platform, also known as the 5' cloverleaf (5'CL). Here, we present a biophysical analysis of the 5'CL conformation of three enterovirus serotypes under various ionic conditions, utilizing CD spectroscopy, size-exclusion chromatography, and small-angle X-ray scattering. In general, a tendency toward a smaller monomeric hydrodynamic radius in the presence of salts was observed, but the exact structural signature of each 5'CL varied depending upon the serotype. Rhinovirus B14 (RVB14) exhibited at least two monomeric conformations and a low propensity for dimerization, while poliovirus 1 (PV1) showed …

Angiogenin-Catalyzed Cleavage Within Trna Anticodon-Loops Identified By Cp-Rna-Seq, Megumi Shigematsu, Ryuma Matsubara, Justin Gumas, Takuya Kawamura, Yohei Kirino

Computational Medicine Center Faculty Papers

Angiogenin (Ang), an endoribonuclease belonging to the RNase A superfamily, cleaves the anticodon-loops of tRNAs to produce tRNA-half molecules. Although previous studies have demonstrated the involvement of Ang in the pathobiology of neurodegenerative disorders, the characterization of Ang-generated tRNA halves in neuronal cells remains limited. This is partly due to the technical limitations of standard RNA-seq methods, which cannot capture Ang-generated RNAs containing a 2',3'-cyclic phosphate (cP). In this report, we established an Ang-treatment model using SH-SY5Y, a human neuroblastoma cell line, and demonstrated Ang-dependent accumulation of tRNA halves. By performing cP-RNA-seq, which selectively captures cP-containing RNAs, we identified Ang-generated …

Differential Infiltration Of Key Immune T-Cell Populations Across Malignancies Varying By Immunogenic Potential And The Likelihood Of Response To Immunotherapy., Islam Eljilany, Sam Coleman, Aik Choon Tan, Martin D. Mccarter, John Carpten, Howard Colman, Abdul Rafeh Naqash, Igor Puzanov, Susanne Arnold, Michelle L. Churchman, Daniel Spakowicz, Bodour Salhia, Julian Marin, Shridar Ganesan, Aakrosh Ratan, Craig Shriver, Patrick Hwu, William S. Dalton, George J. Weiner, Jose R. Conejo-Garcia, Paulo Rodriguez, Ahmad A. Tarhini

Markey Cancer Center Faculty Publications

Background: Solid tumors vary by the immunogenic potential of the tumor microenvironment (TME) and the likelihood of response to immunotherapy. The emerging literature has identified key immune cell populations that significantly impact immune activation or suppression within the TME. This study investigated candidate T-cell populations and their differential infiltration within different tumor types as estimated from mRNA co-expression levels of the corresponding cellular markers.

Methods: We analyzed the mRNA co-expression levels of cellular biomarkers that define stem-like tumor-infiltrating lymphocytes (TILs), tissue-resident memory T-cells (TRM), early dysfunctional T-cells, late dysfunctional T-cells, activated-potentially anti-tumor (APA) T-cells and Butyrophilin 3A (BTN3A) isoforms, utilizing …

Diverse Pathways In Gpcr-Mediated Activation Of Ca2+ Mobilization In Hek293 Cells, Francesco De Pascali, Asuka Inoue, Jeffrey L. Benovic

Department of Biochemistry and Molecular Biology Faculty Papers

G protein-coupled receptors transduce extracellular stimuli into intracellular signaling. Ca²⁺ is a well-known second messenger that can be induced by G protein-coupled receptor activation through the primary canonical pathways involving Gα_q- and Gβγ-mediated activation of phospholipase C-β (PLCβ). While some G_s-coupled receptors are shown to trigger Ca²⁺ mobilization, underlying mechanisms remain elusive. Here, we evaluated whether G_s-coupled receptors including the β₂-adrenergic receptor (β₂AR) and the prostaglandin EP₂ and EP₄ receptors (EP₂R and EP₄R) that are endogenously expressed in human embryonic kidney 293 …

Post-Transcriptional Methylation Of Mitochondrial-Trna Differentially Contributes To Mitochondrial Pathology, Sunita Maharjan, Howard Gamper, Yuka Yamaki, Thomas W. Christian, Robert Y. Henley, Nan-Sheng Li, Takeo Suzuki, Tsutomu Suzuki, Joseph A. Piccirilli, Meni Wanunu, Erin L. Seifert, Douglas C. Wallace, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Human mitochondrial tRNAs (mt-tRNAs), critical for mitochondrial biogenesis, are frequently associated with pathogenic mutations. These mt-tRNAs have unusual sequence motifs and require post-transcriptional modifications to stabilize their fragile structures. However, whether a modification that stabilizes a wild-type (WT) mt-tRNA would also stabilize its pathogenic variants is unknown. Here we show that the N¹-methylation of guanosine at position 9 (m¹G9) of mt-Leu(UAA), while stabilizing the WT tRNA, has a destabilizing effect on variants associated with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes). This differential effect is further demonstrated, as removal of the m¹G9 …

Nanopore Signal Deviations From Pseudouridine Modifications In Rna Are Sequence-Specific: Quantification Requires Dedicated Synthetic Controls, Amr Makhamreh, Sepideh Tavakoli, Ali Fallahi, Xinqi Kang, Howard Gamper, Mohammad Nabizadehmashhadtoroghi, Miten Jain, Ya-Ming Hou, Sara H Rouhanifard, Meni Wanunu

Department of Biochemistry and Molecular Biology Faculty Papers

Chemical modifications to mRNA respond dynamically to environmental cues and are important modulators of gene expression. Nanopore direct RNA sequencing has been applied for assessing the presence of pseudouridine (ψ) modifications through basecalling errors and signal analysis. These approaches strongly depend on the sequence context around the modification, and the occupancies derived from these measurements are not quantitative. In this work, we combine direct RNA sequencing of synthetic RNAs bearing site-specific modifications and supervised machine learning models (ModQuant) to achieve near-analytical, site-specific ψ quantification. Our models demonstrate that the ionic current signal features important for accurate ψ classification are sequence …

The C-Terminal 4cxxc-Type Zinc Finger Domain Of Cdca7 Recognizes Hemimethylated Dna And Modulates Activities Of Chromatin Remodeling Enzyme Hells, Akeo Shinkai, Hideharu Hashimoto, Chikako Shimura, Hiroaki Fujimoto, Kei Fukuda, Naoki Horikoshi, Masaki Okano, Hitoshi Niwa, Erik W Debler, Hitoshi Kurumizaka, Yoichi Shinkai

Department of Biochemistry and Molecular Biology Faculty Papers

The chromatin-remodeling enzyme helicase lymphoid-specific (HELLS) interacts with cell division cycle-associated 7 (CDCA7) on nucleosomes and is involved in the regulation of DNA methylation in higher organisms. Mutations in these genes cause immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome, which also results in DNA hypomethylation of satellite repeat regions. We investigated the functional domains of human CDCA7 in HELLS using several mutant CDCA7 proteins. The central region is critical for binding to HELLS, activation of ATPase, and nucleosome sliding activities of HELLS-CDCA7. The N-terminal region tends to inhibit ATPase activity. The C-terminal 4CXXC-type zinc finger domain contributes to CpG …

Engineered Nls-Chimera Downregulates Expression Of Aggregation-Prone Endogenous Fus, Miyuki Hayashi, Amandeep Girdhar, Ying-Hui Ko, Kevin Kim, Jacquelyn Depierro, Joseph R. Buchler, Nikhita Arunprakash, Aditya Bajaj, Gino Cingolani, Lin Guo

Department of Biochemistry and Molecular Biology Faculty Papers

Importin β-superfamily nuclear import receptors (NIRs) mitigate mislocalization and aggregation of RNA-binding proteins (RBPs), like FUS and TDP-43, which are implicated in neurodegenerative diseases. NIRs potently disaggregate RBPs by recognizing their nuclear localization signal (NLS). However, disease-causing mutations in NLS compromise NIR binding and activity. Here, we define features that characterize the anti-aggregation activity of NIR and NLS. We find that high binding affinity between NIR and NLS, and optimal NLS location relative to the aggregating domain plays a role in determining NIR disaggregation activity. A designed FUS chimera (FUS_IBB), carrying the importin β binding (IBB) domain, is …

Non-Redundant Roles For The Human Mrna Decapping Cofactor Paralogs Dcp1a And Dcp1b, Ivana Vukovic, Samantha M. Barnada, Jonathan W. Ruffin, Jon Karlin, Ravi Kumar Lokareddy, Gino Cingolani, Steven B. Mcmahon

Department of Medicine Faculty Papers

Eukaryotic gene expression is regulated at the transcriptional and post-transcriptional levels, with disruption of regulation contributing significantly to human diseases. The 5' m7G mRNA cap is a central node in post-transcriptional regulation, participating in both mRNA stabilization and translation efficiency. In mammals, DCP1a and DCP1b are paralogous cofactor proteins of the mRNA cap hydrolase DCP2. As lower eukaryotes have a single DCP1 cofactor, the functional advantages gained by this evolutionary divergence remain unclear. We report the first functional dissection of DCP1a and DCP1b, demonstrating that they are non-redundant cofactors of DCP2 with unique roles in decapping complex integrity and specificity. …

Emerin Deficiency Drives Mcf7 Cells To An Invasive Phenotype, Emily Hansen, Christal Rolling, Matthew Wang, James M Holaska

Rowan-Virtua School of Osteopathic Medicine Departmental Research

During metastasis, cancer cells traverse the vasculature by squeezing through very small gaps in the endothelium. Thus, nuclei in metastatic cancer cells must become more malleable to move through these gaps. Our lab showed invasive breast cancer cells have 50% less emerin protein resulting in smaller, misshapen nuclei, and higher metastasis rates than non-cancerous controls. Thus, emerin deficiency was predicted to cause increased nuclear compliance, cell migration, and metastasis. We tested this hypothesis by downregulating emerin in noninvasive MCF7 cells and found emerin knockdown causes smaller, dysmorphic nuclei, resulting in increased impeded cell migration. Emerin reduction in invasive breast cancer …