Medicine and Health Sciences Commons^™

Characterization Of A New Whim Syndrome Mutant Reveals Mechanistic Differences In Regulation Of The Chemokine Receptor Cxcr4, Jiansong Luo, Francesco De Pascali, G Wendell Richmond, Amer M Khojah, Jeffrey L Benovic

Department of Biochemistry and Molecular Biology Faculty Papers

WHIM syndrome is a rare immunodeficiency disorder that is characterized by warts, hypogammaglobulinemia, infections, and myelokathexis. While several gain-of-function mutations that lead to C-terminal truncations, frame shifts and point mutations in the chemokine receptor CXCR4 have been identified in WHIM syndrome patients, the functional effect of these mutations are not fully understood. Here, we report on a new WHIM syndrome mutation that results in a frame shift within the codon for Ser339 (S339fs5) and compare the properties of S339fs5 with wild-type CXCR4 and a previously identified WHIM syndrome mutant, R334X. The S339fs5 and R334X mutants exhibited significantly increased signaling compared …

Platelet Micrornas Inhibit Primary Tumor Growth Via Broad Modulation Of Tumor Cell Mrna Expression In Ectopic Pancreatic Cancer In Mice, Jeremy G.T. Wurtzel, Sophia Lazar, Sonali Sikder, Kathy Q Cai, Igor Astsaturov, Andrew S Weyrich, Jesse W Rowley, Lawrence E. Goldfinger

Department of Medicine Faculty Papers

We investigated the contributions of platelet microRNAs (miRNAs) to the rate of growth and regulation of gene expression in primary ectopic tumors using mouse models. We previously identified an inhibitory role for platelets in solid tumor growth, mediated by tumor infiltration of platelet microvesicles (microparticles) which are enriched in platelet-derived miRNAs. To investigate the specific roles of platelet miRNAs in tumor growth models, we implanted pancreatic ductal adenocarcinoma cells as a bolus into mice with megakaryocyte-/platelet-specific depletion of mature miRNAs. We observed an ~50% increase in the rate of growth of ectopic primary tumors in these mice compared to controls …

Time-Resolved Cryo-Em Visualizes Ribosomal Translocation With Ef-G And Gtp, Christine E Carbone, Anna B Loveland, Howard Gamper, Ya-Ming Hou, Gabriel Demo, Andrei A Korostelev

Department of Biochemistry and Molecular Biology Faculty Papers

During translation, a conserved GTPase elongation factor-EF-G in bacteria or eEF2 in eukaryotes-translocates tRNA and mRNA through the ribosome. EF-G has been proposed to act as a flexible motor that propels tRNA and mRNA movement, as a rigid pawl that biases unidirectional translocation resulting from ribosome rearrangements, or by various combinations of motor- and pawl-like mechanisms. Using time-resolved cryo-EM, we visualized GTP-catalyzed translocation without inhibitors, capturing elusive structures of ribosome•EF-G intermediates at near-atomic resolution. Prior to translocation, EF-G binds near peptidyl-tRNA, while the rotated 30S subunit stabilizes the EF-G GTPase center. Reverse 30S rotation releases Pi and translocates peptidyl-tRNA and …

Targeting Oncogenic Gαq/11 In Uveal Melanoma, Dominic Lapadula, Jeffrey L Benovic

Department of Biochemistry and Molecular Biology Faculty Papers

Uveal melanoma is the most common intraocular cancer in adults and arises from the transformation of melanocytes in the uveal tract. While treatment of the primary tumor is often effective, 36–50% of patients develop metastatic disease primarily to the liver. While various strategies have been used to treat the metastatic disease, there remain no effective treatments that improve survival. Significant insight has been gained into the pathways that are altered in uveal melanoma, with mutually exclusive activating mutations in the GNAQ and GNA11 genes being found in over 90% of patients. These genes encode the alpha subunits of the hetetrotrimeric …

Promoter Considerations In The Design Of Lentiviral Vectors For Use In Treating Lysosomal Storage Diseases, Estera Rintz, Takashi Higuchi, Hiroshi Kobayashi, Deni S Galileo, Grzegorz Wegrzyn, Shunji Tomatsu

Department of Pediatrics Faculty Papers

More than 50 lysosomal storage diseases (LSDs) are associated with lysosomal dysfunctions with the frequency of 1:5,000 live births. As a result of missing enzyme activity, the lysosome dysfunction accumulates undegraded or partially degraded molecules, affecting the entire body. Most of them are life-threatening diseases where patients could die within the first or second decade of life. Approximately 20 LSDs have the approved treatments, which do not provide the cure for the disorder. Therefore, the delivery of missing genes through gene therapy is a promising approach for LSDs. Over the years, ex vivo lentiviral-mediated gene therapy for LSDs has been …

Tera-Seq: True End-To-End Sequencing Of Native Rna Molecules For Transcriptome Characterization, Fadia Ibrahim, Jan Oppelt, Manolis Maragkakis, Zissimos Mourelatos

Department of Biochemistry and Molecular Biology Faculty Papers

Direct sequencing of single, native RNA molecules through nanopores has a strong potential to transform research in all aspects of RNA biology and clinical diagnostics. The existing platform from Oxford Nanopore Technologies is unable to sequence the very 5′ ends of RNAs and is limited to polyadenylated molecules. Here, we develop True End-to-end RNA Sequencing (TERA-Seq), a platform that addresses these limitations, permitting more thorough transcriptome characterization. TERA-Seq describes both poly-and non-polyadenylated RNA molecules and accurately identifies their native 5′ and 3′ ends by ligating uniquely designed adapters that are sequenced along with the transcript. We find that capped, full-length …

Expression And Purification Of Phage T7 Ejection Proteins For Cryo-Em Analysis, Nicholas A. Swanson, Ravi K Lokareddy, Fenglin Li, Chun-Feng Hou, Mikhail Pavlenok, Michael Niederweis, Gino Cingolani

Department of Biochemistry and Molecular Biology Faculty Papers

Bacteriophages of the Podoviridae family densely package their genomes into precursor capsids alongside internal virion proteins called ejection proteins. In phage T7 these proteins (gp14, gp15, and gp16) are ejected into the host envelope forming a DNA-ejectosome for genome delivery. Here, we describe the purification and characterization of recombinant gp14, gp15, and gp16. This protocol was used for high-resolution cryo-EM structure analysis of the T7 periplasmic tunnel and can be adapted to study ejection proteins from other phages. For complete details on the use and execution of this protocol, please refer to Swanson et al.

Inability To Switch From Arid1a-Baf To Arid1b-Baf Impairs Exit From Pluripotency And Commitment Towards Neural Crest Formation In Arid1b-Related Neurodevelopmental Disorders, Luca Pagliaroli, Patrizia Porazzi, Alyxandra T Curtis, Chiara Scopa, Harald M M Mikkers, Christian Freund, Lucia Daxinger, Sandra Deliard, Sarah A Welsh, Sarah Offley, Connor A Ott, Bruno Calabretta, Samantha A Brugmann, Gijs W E Santen, Marco Trizzino

Department of Biochemistry and Molecular Biology Faculty Papers

Subunit switches in the BAF chromatin remodeler are essential during development. ARID1B and its paralog ARID1A encode for mutually exclusive BAF subunits. De novo ARID1B haploinsufficient mutations cause neurodevelopmental disorders, including Coffin-Siris syndrome, which is characterized by neurological and craniofacial features. Here, we leveraged ARID1B+/- Coffin-Siris patient-derived iPSCs and modeled cranial neural crest cell (CNCC) formation. We discovered that ARID1B is active only during the first stage of this process, coinciding with neuroectoderm specification, where it is part of a lineage-specific BAF configuration (ARID1B-BAF). ARID1B-BAF regulates exit from pluripotency and lineage commitment by attenuating thousands of enhancers and genes of …

Zebrafish Paralogs Brd2a And Brd2b Are Needed For Proper Circulatory, Excretory And Central Nervous System Formation And Act As Genetic Antagonists During Development, Gregory L Branigan, Kelly S Olsen, Isabella Burda, Matthew W Haemmerle, Jason Ho, Alexandra Venuto, Nicholas D D'Antonio, Ian E Briggs, Angela J Dibenedetto

Department of Biochemistry and Molecular Biology Faculty Papers

Brd2 belongs to the BET family of epigenetic transcriptional co-regulators that act as adaptor-scaffolds for the assembly of chromatin-modifying complexes and other factors at target gene promoters. Brd2 is a protooncogene and candidate gene for juvenile myoclonic epilepsy in humans, a homeobox gene regulator in Drosophila, and a maternal-zygotic factor and cell death modulator that is necessary for normal development of the vertebrate central nervous system (CNS). As two copies of Brd2 exist in zebrafish, we use antisense morpholino knockdown to probe the role of paralog Brd2b, as a comparative study to Brd2a, the ortholog of human Brd2. A deficiency …

Global Gene Expression Analysis Of Systemic Sclerosis Myofibroblasts Demonstrates A Marked Increase In The Expression Of Multiple Nbpf Genes, Giuseppina Abignano, Heidi Hermes, Sonsoles Piera-Velazquez, Sankar Addya, Francesco Del Galdo, Sergio A. Jimenez

Kimmel Cancer Center Faculty Papers

Myofibroblasts are the key effector cells responsible for the exaggerated tissue fibrosis in Systemic Sclerosis (SSc). Despite their importance to SSc pathogenesis, the specific transcriptome of SSc myofibroblasts has not been described. The purpose of this study was to identify transcriptome differences between SSc myofibroblasts and non-myofibroblastic cells. Alpha smooth muscle actin (α-SMA) expressing myofibroblasts and α-SMA negative cells were isolated employing laser capture microdissection from dermal cell cultures from four patients with diffuse SSc of recent onset. Total mRNA was extracted from both cell populations, amplified and analyzed employing microarrays. Results for specific genes were validated by Western blots …

The Penn State Protein Ladder System For Inexpensive Protein Molecular Weight Markers, Ryan T Santilli, John E Williamson, Yoshitaka Shibata, Rosalie P Sowers, Andrew N. Fleischman, Song Tan

Department of Anesthesiology Faculty Papers

We have created the Penn State Protein Ladder system to produce protein molecular weight markers easily and inexpensively (less than a penny a lane). The system includes plasmids which express 10, 15, 20, 30, 40, 50, 60, 80 and 100 kD proteins in E. coli. Each protein migrates appropriately on SDS-PAGE gels, is expressed at very high levels (10–50 mg per liter of culture), is easy to purify via histidine tags and can be detected directly on Western blots via engineered immunoglobulin binding domains. We have also constructed plasmids to express 150 and 250 kD proteins. For more efficient production, …

Dna Polymerase Θ: A Cancer Drug Target With Reverse Transcriptase Activity, Xiaojiang Chen, Richard T. Pomerantz

Department of Biochemistry and Molecular Biology Faculty Papers

The emergence of precision medicine from the development of Poly (ADP‐ribose) polymerase (PARP) inhibitors that preferentially kill cells defective in homologous recombination has sparked wide interest in identifying and characterizing additional DNA repair enzymes that are synthetic lethal with HR factors. DNA polymerase theta (Polθ) is a validated anti‐cancer drug target that is synthetic lethal with HR factors and other DNA repair proteins and confers cellular resistance to various genotoxic cancer therapies. Since its initial characterization as a helicase‐polymerase fusion protein in 2003, many exciting and unexpected activities of Polθ in microhomology‐mediated end‐joining (MMEJ) and translesion synthesis (TLS) have been …

Characterization Of Hnrnpa1 Mutations Defines Diversity In Pathogenic Mechanisms And Clinical Presentation., Danique Beijer, Hong Joo Kim, Lin Guo, Kevin O'Donovan, Inès Mademan, Tine Deconinck, Kristof Van Schil, Charlotte M Fare, Lauren E Drake, Alice F Ford, Andrzej Kochański, Dagmara Kabzińska, Nicolas Dubuisson, Peter Van Den Bergh, Nicol C Voermans, Richard Jlf Lemmers, Silvère M Van Der Maarel, Devon Bonner, Jacinda B Sampson, Matthew T Wheeler, Anahit Mehrabyan, Steven Palmer, Peter De Jonghe, James Shorter, J Paul Taylor, Jonathan Baets

Department of Biochemistry and Molecular Biology Faculty Papers

Mutations in HNRNPA1 encoding heterogeneous nuclear ribonucleoprotein (hnRNP) A1 are a rare cause of amyotrophic lateral sclerosis (ALS) and multisystem proteinopathy (MSP). hnRNPA1 is part of the group of RNA-binding proteins (RBPs) that assemble with RNA to form RNPs. hnRNPs are concentrated in the nucleus and function in pre-mRNA splicing, mRNA stability, and the regulation of transcription and translation. During stress, hnRNPs, mRNA, and other RBPs condense in the cytoplasm to form stress granules (SGs). SGs are implicated in the pathogenesis of (neuro-)degenerative diseases, including ALS and inclusion body myopathy (IBM). Mutations in RBPs that affect SG biology, including FUS, …

Analysis Of The Dna-Binding Properties Of Alx1, An Evolutionarily Conserved Regulator Of Skeletogenesis In Echinoderms, Jennifer Guerrero-Santoro, Jian Ming Khor, Ayşe Haruka Açıkbaş, James B. Jaynes, Charles A Ettensohn

Department of Biochemistry and Molecular Biology Faculty Papers

Alx1, a homeodomain-containing transcription factor, is a highly conserved regulator of skeletogenesis in echinoderms. In sea urchins, Alx1 plays a central role in the differentiation of embryonic primary mesenchyme cells (PMCs) and positively regulates the transcription of most biomineralization genes expressed by these cells. The alx1 gene arose via duplication and acquired a skeletogenic function distinct from its paralog (alx4) through the exonization of a 41-amino acid motif (the D2 domain). Alx1 and Alx4 contain glutamine-50 paired-type homeodomains, which interact preferentially with palindromic binding sites in vitro. Chromatin immunoprecipitation sequencing (ChIP-seq) studies have shown, however, that Alx1 binds both to …

Polθ Reverse Transcribes Rna And Promotes Rna-Templated Dna Repair, Gurushankar Chandramouly, Jiemin Zhao, Shane Mcdevitt, Timur Rusanov, Trung Hoang, Nikita Borisonnik, Taylor Treddinick, Felicia Wednesday Lopezcolorado, Tatiana Kent, Labiba Siddique, Joseph Mallon, Jacklyn Huhn, Zainab Shoda, Ekaterina Kashkina, Alessandra Brambati, Jeremy M Stark, Xiaojiang S Chen, Richard Pomerantz

Department of Biochemistry and Molecular Biology Faculty Papers

Genome-embedded ribonucleotides arrest replicative DNA polymerases (Pols) and cause DNA breaks. Whether mammalian DNA repair Pols efficiently use template ribonucleotides and promote RNA-templated DNA repair synthesis remains unknown. We find that human Polθ reverse transcribes RNA, similar to retroviral reverse transcriptases (RTs). Polθ exhibits a significantly higher velocity and fidelity of deoxyribonucleotide incorporation on RNA versus DNA. The 3.2-Å crystal structure of Polθ on a DNA/RNA primer-template with bound deoxyribonucleotide reveals that the enzyme undergoes a major structural transformation within the thumb subdomain to accommodate A-form DNA/RNA and forms multiple hydrogen bonds with template ribose 2'-hydroxyl groups like retroviral RTs. …

Hypercalcemia Of Malignancy Attributed To Cosecretion Of Pth And Pthrp In Lung Adenocarcinoma, Jeffrey Kroopnick, Ubaldo E. Martinez-Outshoorn, Madalina Tuluc, Caroline S Kim

Department of Medical Oncology Faculty Papers

Introduction: Hypercalcemia of malignancy (HCM) portends a very poor prognosis, and no established guidelines exist regarding its management. Most instances of HCM are due to local osteolysis or secretion of parathyroid hormone related-peptide, while less than 1% of all cases are due to ectopic secretion of parathyroid hormone.

Case report: We present an unusual case of HCM due to proposed cosecretion of both parathyroid hormone and parathyroid hormone-related protein in a 36-year-old man with a poorly differentiated lung adenocarcinoma. The patient's hypercalcemia was refractory to conventional measures, including intravenous bisphosphonate therapy (zoledronic acid), and was improved with administration of denosumab. …

An Insulator Blocks Access To Enhancers By An Illegitimate Promoter, Preventing Repression By Transcriptional Interference., Miki Fujioka, Anastasiya Nezdyur, James B. Jaynes

Department of Biochemistry and Molecular Biology Faculty Papers

Several distinct activities and functions have been described for chromatin insulators, which separate genes along chromosomes into functional units. Here, we describe a novel mechanism of functional separation whereby an insulator prevents gene repression. When the homie insulator is deleted from the end of a Drosophila even skipped (eve) locus, a flanking P-element promoter is activated in a partial eve pattern, causing expression driven by enhancers in the 3' region to be repressed. The mechanism involves transcriptional read-through from the flanking promoter. This conclusion is based on the following. Read-through driven by a heterologous enhancer is sufficient to repress, even …

Polθ Promotes The Repair Of 5'-Dna-Protein Crosslinks By Microhomology-Mediated End-Joining, Gurushankar Chandramouly, Shuren Liao, Timur Rusanov, Nikita Borisonnik, Marissa L Calbert, Tatiana Kent, Katherine Sullivan-Reed, Umeshkumar Vekariya, Ekaterina Kashkina, Tomasz Skorski, Hong Yan, Richard T Pomerantz

Department of Biochemistry and Molecular Biology Faculty Papers

DNA polymerase θ (Polθ) confers resistance to chemotherapy agents that cause DNA-protein crosslinks (DPCs) at double-strand breaks (DSBs), such as topoisomerase inhibitors. This suggests Polθ might facilitate DPC repair by microhomology-mediated end-joining (MMEJ). Here, we investigate Polθ repair of DSBs carrying DPCs by monitoring MMEJ in Xenopus egg extracts. MMEJ in extracts is dependent on Polθ, exhibits the MMEJ repair signature, and efficiently repairs 5' terminal DPCs independently of non-homologous end-joining and the replisome. We demonstrate that Polθ promotes the repair of 5' terminal DPCs in mammalian cells by using an MMEJ reporter and find that Polθ confers resistance to …

The Evolutionary Conserved Swi/Snf Subunits Arid1a And Arid1b Are Key Modulators Of Pluripotency And Cell-Fate Determination, Luca Pagliaroli, Marco Trizzino

Department of Biochemistry and Molecular Biology Faculty Papers

Organismal development is a process that requires a fine-tuned control of cell fate and identity, through timely regulation of lineage-specific genes. These processes are mediated by the concerted action of transcription factors and protein complexes that orchestrate the interaction between cis-regulatory elements (enhancers, promoters) and RNA Polymerase II to elicit transcription. A proper understanding of these dynamics is essential to elucidate the mechanisms underlying developmental diseases. Many developmental disorders, such as Coffin-Siris Syndrome, characterized by growth impairment and intellectual disability are associated with mutations in subunits of the SWI/SNF chromatin remodeler complex, which is an essential regulator of transcription. ARID1B …

Historical Perspective Of The G Protein-Coupled Receptor Kinase Family., Jeffrey L Benovic

Department of Biochemistry and Molecular Biology Faculty Papers

Agonist activation of G protein-coupled receptors promotes sequential interaction of the receptor with heterotrimeric G proteins, G protein-coupled receptor kinases (GRKs), and arrestins. GRKs play a central role in mediating the switch from G protein to arrestin interaction and thereby control processes such as receptor desensitization and trafficking and arrestin-mediated signaling. In this review, I provide a historical perspective on some of the early studies that identified the family of GRKs with a primary focus on the non-visual GRKs. These studies included identification, purification, and cloning of the β-adrenergic receptor kinase in the mid- to late-1980s and subsequent cloning and …

Three-Dimensional Structure Of Human Cyclooxygenase (Hcox)-1., Morena Miciaccia, Benny Danilo Belviso, Mariaclara Iaselli, Gino Cingolani, Savina Ferorelli, Marianna Cappellari, Paola Loguercio Polosa, Maria Grazia Perrone, Rocco Caliandro, Antonio Scilimati

Department of Biochemistry and Molecular Biology Faculty Papers

The beneficial effects of Cyclooxygenases (COX) inhibitors on human health have been known for thousands of years. Nevertheless, COXs, particularly COX-1, have been linked to a plethora of human diseases such as cancer, heart failure, neurological and neurodegenerative diseases only recently. COXs catalyze the first step in the biosynthesis of prostaglandins (PGs) and are among the most important mediators of inflammation. All published structural work on COX-1 deals with the ovine isoenzyme, which is easier to produce in milligram-quantities than the human enzyme and crystallizes readily. Here, we report the long-sought structure of the human cyclooxygenase-1 (hCOX-1) that we refined …

Dna Mismatch Repair And Its Role In Huntington's Disease, Ravi R Iyer, Anna Pluciennik

Department of Biochemistry and Molecular Biology Faculty Papers

DNA mismatch repair (MMR) is a highly conserved genome stabilizing pathway that corrects DNA replication errors, limits chromosomal rearrangements, and mediates the cellular response to many types of DNA damage. Counterintuitively, MMR is also involved in the generation of mutations, as evidenced by its role in causing somatic triplet repeat expansion in Huntington's disease (HD) and other neurodegenerative disorders. In this review, we discuss the current state of mechanistic knowledge of MMR and review the roles of key enzymes in this pathway. We also present the evidence for mutagenic function of MMR in CAG repeat expansion and consider mechanistic hypotheses …

Distinct Mechanisms Control Genome Recognition By P53 At Its Target Genes Linked To Different Cell Fates., Marina Farkas, Hideharu Hashimoto, Yingtao Bi, Ramana V Davuluri, Lois Resnick-Silverman, James J. Manfredi, Erik W. Debler, Steven B. Mcmahon

Department of Biochemistry and Molecular Biology Faculty Papers

The tumor suppressor p53 integrates stress response pathways by selectively engaging one of several potential transcriptomes, thereby triggering cell fate decisions (e.g., cell cycle arrest, apoptosis). Foundational to this process is the binding of tetrameric p53 to 20-bp response elements (REs) in the genome (RRRCWWGYYYN_0-13RRRCWWGYYY). In general, REs at cell cycle arrest targets (e.g. p21) are of higher affinity than those at apoptosis targets (e.g., BAX). However, the RE sequence code underlying selectivity remains undeciphered. Here, we identify molecular mechanisms mediating p53 binding to high- and low-affinity REs by showing that key determinants of the code are embedded …