Biochemistry Commons^™

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 …

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. …

Chromatin Insulators Homie And Nhomie Can Interact With Distant Copies Either Together Or Separately, With Distinct Outcomes For Enhancer-Promoter Interactions, Miki Fujioka, Wenfan Ke, Paul Schedl, James B. Jaynes

Department of Biochemistry and Molecular Biology Faculty Papers

Chromatin insulators, a.k.a. boundary elements, separate regions of the chromosome with distinct chromatin characteristics, including distinct histone modifications. This activity affects gene expression by allowing chromatin domains to be stably regulated and maintained. Insulators also block enhancer-promoter interactions and, somewhat paradoxically, facilitate other interactions, particularly when they stitch together distant regions of the chromosome by pairing with specific partners. Here we explore how long-range interactions facilitated by insulator pairing are affected by the presence of two potentially competing partners. Our results show that when two partners are present, they can reduce each other's effects on distant gene expression, suggesting that …

Structure Of Ergosteryl-Aspartate Synthase Reveals How An Entrapped Trna Is Used Like A Prosthetic Swinging Arm In The Synthesis Of Aminoacylated Sterols, Hanako Murayama, Nathaniel Yakobov, Nassira Mahmoudi, Sasha Legrosdidier, Nicolas Fournier, Solène Zuttion, Kanata Matsumoto, Michihiro Nishimura, Jingwei Ji, Bruno Senger, Laurence Huck, Howard Gamper, Yoshiaki Kise, Ralph Kleiner, Mathieu Frechin, Ya-Ming Hou, Hubert Becker, Yuzuru Itoh, Frédéric Fischer, Osamu Nureki

Department of Biochemistry and Molecular Biology Faculty Papers

Ergosteryl-3β-O-L-aspartate synthase (ErdS) catalyzes tRNA-dependent aspartylation of ergosterol, a lipid essential for fungal cell membrane integrity. However, the functional significance of ergosteryl-aspartate and the molecular mechanisms underlying its synthesis remain unclear. Here, we show that ErdS localization is highly dynamic and that Erg-Asp is required for proper hyphal growth, sporulation, and spore germination, and likely influences stress tolerance. The cryo-electron microscopy structure of ErdS revealed an unprecedented sterol-binding pocket. In addition, the structures in complex with a non-hydrolyzable Asp-N-tRNAAsp show a tRNA-guided intramolecular aminoacyl transfer mechanism between two functional domains of the enzyme. The CCA end of tRNAAsp undergoes a …

Crystal Structure Of Mouse Dxo In Complex With The Udp-N-Acetylglucosamine Cap And Molecular Mechanism For The Decapping Reactions, Najeeb Ullah, Selom K. Doamekpor, Liang Tong

Department of Biochemistry and Molecular Biology Faculty Papers

Noncanonical metabolite 5' caps have recently been identified on RNAs, and the DXO/Rai1 family of enzymes can remove these caps in eukaryotes. While the binding modes of NAD, FAD and dephospho-CoA (dpCoA) caps in the active site of mouse DXO have been determined, how DXO recognizes the UDP-glucose (UDP-Glc) and UDP-N-acetylglucosamine (UDP-GlcNAc) caps is not known. In addition, the molecular mechanism by which DXO catalyzes the decapping reactions is still poorly understood, especially the location of the water/hydroxide that attacks the scissile phosphate to initiate the decapping. Here we report the crystal structure of mouse DXO in complex with UDP-GlcNAc …

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 …

Mechanistic Insights Into E. Coli Recovery From Growth Arrest, Ahmed H. Hassan, Yuko Nakano, Howard Gamper, Isao Masuda, Ludmila Vesela, Matyas Pinkas, Sathya Narayanan Nagarajan, Jonathan Dworkin, Gregor Blaha, Ya-Ming Hou, Gabriel Demo

Department of Biochemistry and Molecular Biology Faculty Papers

Bacteria survive hostile conditions by shutting down protein synthesis, but how they restart growth remains poorly understood. Here, we use an E. coli ΔrimM strain, which exhibits a prolonged growth arrest, as a model to investigate how bacteria recover from this state and restore protein synthesis. RimM is a conserved ribosome maturation factor for the 3'-major (head) domain of the 16S rRNA within the bacterial 30S subunit. The loss of RimM causes a longer delay in recovery than other 30S maturation factors, including RbfA. Cryo-EM analysis of ΔrimM ribosomes suggests a delayed recruitment of ribosomal proteins to the 30S head …

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 …

An Antioxidant Cocktail Of Tert-Butylhydroquinone And A Manganese Porphyrin Induces Toxic Levels Of Oxidative Stress In Cancer Cells, Sandra Tamarin, Hannah Jung, Joseph Lamorte, Laura Biesterveld, Gabriel Piñero, Grace Turchetta, Molly Myers, Rebecca Oberley-Deegan, Aimee Eggler

Student Papers, Posters & Projects

Despite significant advancement in cancer treatments, therapies with minimal toxicity to healthy cells are still limited. One targetable weakness of cancer cells is their sensitivity to oxidative stress. We find that the combination of two antioxidants—the common food additive tert-butylhydroquinone (tBHQ) and a manganese porphyrin in clinical trials, MnTnBuOE-2-PyP5+ (MnBuOE)—increases oxidative stress and causes apoptotic death in several cancer cell lines, but not in mouse primary fibroblasts. Investigating the mechanism of cell death, MnBuOE is observed to catalyze the oxidation of tBHQ, producing the electrophilic quinone tert-butylquinone (tBQ). A critical role for tBQ and its electrophilic character was revealed with …

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 …

Discovery Of 5‑Chlorotryptophan-Containing Antibiotics Through Metabologenomics-Assisted High-Throughput Screening, Chantal D Bader, Isao Masuda, Angela Nichols, Edward Kalkreuter, Dong Yang, Thomas Christian, Yuko Nakano, Ya-Ming Hou, Ben Shen

Department of Biochemistry and Molecular Biology Faculty Papers

Actinomycetota bacteria have specialized in the biosynthesis of antibacterial natural products (NPs), and extract and fraction libraries made from those strains remain a promising source of NP drug leads. Herein, we present a high-throughput screen (HTS), based on engineered Escherichia coli strains expressing the human (Trm5) or bacterial (TrmD) m¹G37 tRNA methyltransferase, to discover NPs as novel anti-Gram-negative antibiotic leads. To harness the evolution of NPs with in vivo activity, the cell-based phenotypic HTS was applied to the Actinomycetota extract and fraction library at the Natural Products Discovery Center (NPDC), the Herbert Wertheim UF Scripps Institute for Biomedical …

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 …

Engineered An Ultrasmall Curcumin Oral Nanoformulation Restores Intestinal Integrity And Gut Microbiota Dysbiosis, Vivek Sharma, Prateeksha Prateeksha, Balwant Paliya, Sateesh Gupta, Sarvendra Singh, Anand Anunay, Sushil Agrahari, Shailendra Singh, Chandana Rao, Saroj Barik, Brahma Singh

Department of Biochemistry and Molecular Biology Faculty Papers

Antibiotic therapy for bacterial infections often disrupts gut microbiota (GM) and intestinal integrity, inducing chronic inflammation and inflammatory bowel diseases. An effective therapeutic intervention is urgently needed to alleviate the aforementioned adverse effects of antibiotics. Curcumin (CUR) reveals great potential to restore intestinal integrity and GM dysbiosis due to its strong antiinflammatory and prebiotic effects. However, the weak solubility and stability of CUR result in limited bioavailability and a short half-life, which restricts its clinical uses. An ultra-small CUR oral nanoformulation was created using a carboxylated galactomannan (cGM), facilitated by hydrogen bonding between the phenolic hydroxyl groups of CUR and …

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 …

Liver-Directed Base Editing Of Abcc6 Prevents Ectopic Calcification In A Variant-Humanized Mouse Model Of Pseudoxanthoma Elasticum, Lauren C. Testa, Dora Obiri-Yeboah, Hooda Said, Ping Qu, Michael A. Levine, Mohamad-Gabriel Alameh, Kiran Musunuru, Qiaoli Li, Xiao Wang

Department of Biochemistry and Molecular Biology Faculty Papers

Pseudoxanthoma elasticum (PXE) is an autosomal recessive connective tissue disorder characterized by ectopic calcification of elastic fibers throughout the skin, retina, and arteries. It is caused by pathogenic variants in ABCC6 , which encodes a transmembrane transporter that primarily localizes to hepatocytes. Loss of ABCC6 function in hepatocytes leads to systemic deficiency of inorganic pyrophosphate (PPi), a potent inhibitor of calcification; such depletion of PPi from the circulation is responsible for multisystemic ectopic calcification seen in PXE. Therefore, liver-targeted variant correction by genome editing and subsequent restoration of systemic PPi may offer a one-and-done therapeutic approach for PXE. The ABCC6 …

Using The Safety Scissors: Dna Resection Regulation At Dna Double-Strand Breaks And Telomeres, Michael M, Soniat, Logan R. Myler

Department of Biochemistry and Molecular Biology Faculty Papers

DNA resection is a universal process in genome maintenance by which one strand of DNA is degraded, leaving the other strand intact. This sometimes highly processive process is critical for many forms of DNA damage repair, replication-coupled repair, meiotic recombination, and telomere maintenance. Therefore, resection must be tightly regulated to prevent genome instability and promote faithful and accurate repair. Here, we review what is known about how resection functions and how it is controlled, using DNA double-strand break repair and telomere maintenance as examples. We address how resection is regulated in three independent steps: resection initiation, long-range processing, and termination. …

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 …

Computational And Imaging Approaches For Precision Characterization Of Bone, Cartilage, And Synovial Biomolecules., Rahul Kumar, Kyle Sporn, Vibhav Prabhakar, Ahab Alnemri, Akshay Khanna, Phani Paladugu, Chirag Gowda, Louis Clarkson, Nasif Zaman, Alireza Tavakkoli

Department of Medicine Faculty Papers

Abstract

Background/Objectives: Degenerative joint diseases (DJDs) involve intricate molecular disruptions within bone, cartilage, and synovial tissues, often preceding overt radiographic changes. These tissues exhibit complex biomolecular architectures and their degeneration leads to microstructural disorganization and inflammation that are challenging to detect with conventional imaging techniques. This review aims to synthesize recent advances in imaging, computational modeling, and sequencing technologies that enable high-resolution, non-invasive characterization of joint tissue health. Methods: We examined advanced modalities including high-resolution MRI (e.g., T1ρ, sodium MRI), quantitative and dual-energy CT (qCT, DECT), and ultrasound elastography, integrating them with radiomics, deep learning, and multi-scale modeling approaches. We …

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, …

Hexasodium Fytate (Snf472 Or Csl525) Inhibits Ectopic Calcification In Various Pseudoxanthoma Elasticum And Calcinosis Cutis Animal Models, Miguel Ferrer, Maria Pérez-Ferrer, Marc Blasco, Ida Jacobs, Qiaoli Li, Olivier Vanakker, Lisa Dangreau, Andrea López, Gianluca Malagraba, Firas Bassissi, Joan Perelló, Carolina Salcedo

Department of Biochemistry and Molecular Biology Faculty Papers

Background/Objectives: Ectopic calcification is a pathological condition characterized by the mineralization of soft tissues due to the deposition of calcium phosphate crystals. Hexasodium fytate (CSL525, previously known as SNF472) is a crystallization inhibitor being developed for the treatment of ectopic calcification-related disorders. Our aim was to investigate CSL525 for the treatment of soft-tissue calcification disorders in animal models of pseudoxanthoma elasticum and calcinosis cutis. Methods: In a first study, abcc6^-/- zebrafish larvae were exposed to 1 mM CSL525 for 7 days or kept under the same conditions without CSL525, and spinal mineralization was quantified. In a second study, abcc6 …

The Guanine Nucleotide Exchange Factor Ric-8a Regulates The Sensitivity Of Constitutively Active Gαq To The Inhibitor Ym-254890, Morgan Dwyer, Jiansong Luo, Tyson Todd, Kendall Blumer, Gregory Tall, Philip Wedegaertner

Department of Biochemistry and Molecular Biology Faculty Papers

Heterotrimeric G proteins are stimulated under normal circumstances by G protein-coupled receptors to promote downstream intracellular signaling. Mutations can occur in αq at glutamine 209 (Q209) that cause constitutive, G protein-coupled receptor independent signaling due to disruption of GTPase activity. Specifically, Q209L/P mutations are oncogenic drivers of uveal melanoma. YM-254890 (YM) has been shown to selectively inhibit both WT and constitutively active (CA) αqQ209L/P by preventing the release of GDP and exchange for GTP, thereby halting downstream signaling. Because αqQL/P are thought to be primarily GTP-bound and GTPase deficient, the current mechanistic understanding of YM inhibition needs further investigation to …

Structural Basis For Intrinsic Strand Displacement Activity Of Mitochondrial Dna Polymerase, Ashok Nayak, Viktoriia Sokolova, Sirelin Sillamaa, Karl Herbine, Juhan Sedman, Dmitry Temiakov

Department of Biochemistry and Molecular Biology Faculty Papers

Members of the Pol A family of DNA polymerases, found across all domains of life, utilize various strategies for DNA strand separation during replication. In higher eukaryotes, mitochondrial DNA polymerase γ relies on the replicative helicase TWINKLE, whereas the yeast ortholog, Mip1, can unwind DNA independently. Using Mip1 as a model, we present a series of high-resolution cryo-EM structures that capture the process of DNA strand displacement. Our data reveal previously unidentified structural elements that facilitate the unwinding of the downstream DNA duplex. Yeast cells harboring Mip1 variants defective in strand displacement exhibit impaired oxidative phosphorylation and loss of mtDNA, …

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 …

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 …

A Kinetic Model For Compound Heterozygous Pathogenic Variants In Tyrosyl-Trna Synthetase Gene Yars2-Associated Neonatal Phenotype, Thomas W Christian, Sunita Maharjan, Sitao Yin, Yuka Yamaki, Isao Masuda, Fenglin Li, Colleen Muraresku, Sheila Clever, Rebecca Ganetzky, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Human genetic disorders are often caused by mutations of compound heterozygosity, where each allele of the mutant gene harbors a different genetic lesion. However, studies of such mutations are hampered due to the lack of an appropriate model. Here we describe a kinetic model of compound heterozygous variants in an obligate enzyme dimer that contains one mutation in one monomer and the other mutation in the second monomer. This enzyme is encoded by human YARS2 for mitochondrial tyrosyl-tRNA synthetase (mt-TyrRS), which aminoacylates tyrosine to mt-tRNA^Tyr. YARS2 is a member of the genes for mt-aminoacyl-tRNA synthetases, where pathogenic mutations …

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 …

Viral Genome Delivery Across Bacterial Cell Surfaces, Stephano M. Iglesias, Fenglin Li, Federica Briani, Gino Cingolani

Department of Biochemistry and Molecular Biology Faculty Papers

In 1952, Hershey and Chase used bacteriophage T2 genome delivery inside Escherichia coli to demonstrate that DNA, not protein, is the genetic material. Over 70 years later, our understanding of bacteriophage structure has grown dramatically, mainly thanks to the cryogenic electron microscopy revolution. In stark contrast, phage genome delivery in prokaryotes remains poorly understood, mainly due to the inherent challenge of studying such a transient and complex process. Here, we review the current literature on viral genome delivery across bacterial cell surfaces. We focus on icosahedral bacterial viruses that we arbitrarily sort into three groups based on the presence and …

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 …

Cryo-Em Analysis Of Pseudomonas Phage Pa193 Structural Components, Stephano M. Iglesias, Chun-Feng Hou, Johnny Reid, Evan Schauer, Renae Geier, Angela Soriaga, Lucy Sim, Lucy Gao, Julian Whitelegge, Pierre Kyme, Deborah Birx, Sebastien Lemire, Gino Cingolani

Department of Biochemistry and Molecular Biology Faculty Papers

The World Health Organization has designated Pseudomonas aeruginosa as a critical pathogen for the development of new antimicrobials. Bacterial viruses, or bacteriophages, have been used in various clinical settings, commonly called phage therapy, to address this growing public health crisis. Here, we describe a high-resolution structural atlas of a therapeutic, contractile-tailed Pseudomonas phage, Pa193. We used bioinformatics, proteomics, and cryogenic electron microscopy single particle analysis to identify, annotate, and build atomic models for 21 distinct structural polypeptide chains forming the icosahedral capsid, neck, contractile tail, and baseplate. We identified a putative scaffolding protein stabilizing the interior of the capsid 5-fold …