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Articles 1 - 30 of 170

Full-Text Articles in Molecular Biology

An Automated Bayesian Pipeline For Rapid Analysis Of Single-Molecule Binding Data, Carlas Smith, Karina Jouravleva, Maximiliaan Huisman, Samson M. Jolly, Phillip D. Zamore, David Grünwald Mar 2019

An Automated Bayesian Pipeline For Rapid Analysis Of Single-Molecule Binding Data, Carlas Smith, Karina Jouravleva, Maximiliaan Huisman, Samson M. Jolly, Phillip D. Zamore, David Grünwald

David Grünwald

Single-molecule binding assays enable the study of how molecular machines assemble and function. Current algorithms can identify and locate individual molecules, but require tedious manual validation of each spot. Moreover, no solution for high-throughput analysis of single-molecule binding data exists. Here, we describe an automated pipeline to analyze single-molecule data over a wide range of experimental conditions. In addition, our method enables state estimation on multivariate Gaussian signals. We validate our approach using simulated data, and benchmark the pipeline by measuring the binding properties of the well-studied, DNA-guided DNA endonuclease, TtAgo, an Argonaute protein from the Eubacterium Thermus thermophilus. We ...


Anti-Drug Antibody Responses Impair Prophylaxis Mediated By Aav-Delivered Hiv-1 Broadly Neutralizing Antibodies, Matthew R. Gardner, Ina Fetzer, Lisa M. Kattenhorn, Meredith E. Davis-Gardner, Amber S. Zhou, Barnett Alfant, Jesse A. Weber, Hema R. Kondur, Jose M. Martinez-Navio, Sebastian P. Fuchs, Ronald C. Desrosiers, Guangping Gao, Jeffrey D. Lifson, Michael Farzan Mar 2019

Anti-Drug Antibody Responses Impair Prophylaxis Mediated By Aav-Delivered Hiv-1 Broadly Neutralizing Antibodies, Matthew R. Gardner, Ina Fetzer, Lisa M. Kattenhorn, Meredith E. Davis-Gardner, Amber S. Zhou, Barnett Alfant, Jesse A. Weber, Hema R. Kondur, Jose M. Martinez-Navio, Sebastian P. Fuchs, Ronald C. Desrosiers, Guangping Gao, Jeffrey D. Lifson, Michael Farzan

Open Access Articles

Adeno-associated virus (AAV) delivery of potent and broadly neutralizing antibodies (bNAbs is a promising approach for the prevention of HIV-1 infection. The immunoglobulin G (IgG)1 subtype is usually selected for this application, because it efficiently mediates antibody effector functions and has a somewhat longer half-life. However, the use of IgG1-Fc has been associated with the generation of anti-drug antibodies (ADAs) that correlate with loss of antibody expression. In contrast, we have shown that expression of the antibody-like molecule eCD4-Ig bearing a rhesus IgG2-Fc domain showed reduced immunogenicity and completely protected rhesus macaques from simian-HIV (SHIV)-AD8 challenges. To directly ...


An Automated Bayesian Pipeline For Rapid Analysis Of Single-Molecule Binding Data, Carlas Smith, Karina Jouravleva, Maximiliaan Huisman, Samson M. Jolly, Phillip D. Zamore, David Grünwald Jan 2019

An Automated Bayesian Pipeline For Rapid Analysis Of Single-Molecule Binding Data, Carlas Smith, Karina Jouravleva, Maximiliaan Huisman, Samson M. Jolly, Phillip D. Zamore, David Grünwald

Open Access Articles

Single-molecule binding assays enable the study of how molecular machines assemble and function. Current algorithms can identify and locate individual molecules, but require tedious manual validation of each spot. Moreover, no solution for high-throughput analysis of single-molecule binding data exists. Here, we describe an automated pipeline to analyze single-molecule data over a wide range of experimental conditions. In addition, our method enables state estimation on multivariate Gaussian signals. We validate our approach using simulated data, and benchmark the pipeline by measuring the binding properties of the well-studied, DNA-guided DNA endonuclease, TtAgo, an Argonaute protein from the Eubacterium Thermus thermophilus. We ...


The Non-Canonical Smc Protein Smchd1 Antagonises Tad Formation And Compartmentalisation On The Inactive X Chromosome, Michal R. Gdula, Tatyana B. Nesterova, Greta Pintacuda, Jonathan Godwin, Ye Zhan, Hakan Ozadam, Michael Mcclellan, Daniella Moralli, Felix Krueger, Catherine M. Green, Wolf Reik, Skirmantas Kriaucionis, Edith Heard, Job Dekker, Neil Brockdorff Jan 2019

The Non-Canonical Smc Protein Smchd1 Antagonises Tad Formation And Compartmentalisation On The Inactive X Chromosome, Michal R. Gdula, Tatyana B. Nesterova, Greta Pintacuda, Jonathan Godwin, Ye Zhan, Hakan Ozadam, Michael Mcclellan, Daniella Moralli, Felix Krueger, Catherine M. Green, Wolf Reik, Skirmantas Kriaucionis, Edith Heard, Job Dekker, Neil Brockdorff

Open Access Articles

The inactive X chromosome (Xi) in female mammals adopts an atypical higher-order chromatin structure, manifested as a global loss of local topologically associated domains (TADs), A/B compartments and formation of two mega-domains. Here we demonstrate that the non-canonical SMC family protein, SmcHD1, which is important for gene silencing on Xi, contributes to this unique chromosome architecture. Specifically, allelic mapping of the transcriptome and epigenome in SmcHD1 mutant cells reveals the appearance of sub-megabase domains defined by gene activation, CpG hypermethylation and depletion of Polycomb-mediated H3K27me3. These domains, which correlate with sites of SmcHD1 enrichment on Xi in wild-type cells ...


Hla-Do Modulates The Diversity Of The Mhc-Ii Self-Peptidome, Padma P. Nanaware, Mollie M. Jurewicz, John D. Leszyk, Scott A. Shaffer, Lawrence J. Stern Dec 2018

Hla-Do Modulates The Diversity Of The Mhc-Ii Self-Peptidome, Padma P. Nanaware, Mollie M. Jurewicz, John D. Leszyk, Scott A. Shaffer, Lawrence J. Stern

Open Access Articles

Presentation of antigenic peptides on MHC-II molecules is essential for tolerance to self and for initiation of immune responses against foreign antigens. DO (HLA-DO in humans, H2-O in mice) is a non-classical MHC-II protein that has been implicated in control of autoimmunity and regulation of neutralizing antibody responses to viruses. These effects likely are related to a role of DO in selecting MHC-II epitopes, but previous studies examining the effect of DO on presentation of selected CD4 T cell epitopes have been contradictory. To understand how DO modulates MHC-II antigen presentation, we characterized the full spectrum of peptides presented by ...


Membrane Protein Nanoparticles: The Shape Of Things To Come, Kailene S. Simon, Naomi L. Pollock, Sarah C. Lee Dec 2018

Membrane Protein Nanoparticles: The Shape Of Things To Come, Kailene S. Simon, Naomi L. Pollock, Sarah C. Lee

Open Access Articles

The use of styrene-maleic acid (SMA) for the purification of a wide range of membrane proteins (MPs) from both prokaryotic and eukaryotic sources has begun to make an impact in the field of MP biology. This method is growing in popularity as a means to purify and thoroughly investigate the structure and function of MPs and biological membranes. The amphiphilic SMA copolymer can effectively extract MPs directly from a native lipid bilayer to form discs approximately 10 nm in diameter. The resulting lipid particles, or styrene-maleic acid lipid particles (SMALPs), contain SMA, protein and membrane lipid. MPs purified in SMALPs ...


Resistance From Afar: Distal Mutation V36m Allosterically Modulates The Active Site To Accentuate Drug Resistance In Hcv Ns3/4a Protease, Aysegul Ozen, Kuan-Hung Lin, Keith P. Romano, Davide Tavella, Alicia Newton, Christos J. Petropoulos, Wei Huang, Cihan Aydin, Celia A. Schiffer Dec 2018

Resistance From Afar: Distal Mutation V36m Allosterically Modulates The Active Site To Accentuate Drug Resistance In Hcv Ns3/4a Protease, Aysegul Ozen, Kuan-Hung Lin, Keith P. Romano, Davide Tavella, Alicia Newton, Christos J. Petropoulos, Wei Huang, Cihan Aydin, Celia A. Schiffer

University of Massachusetts Medical School Faculty Publications

Hepatitis C virus rapidly evolves, conferring resistance to direct acting antivirals. While resistance via active site mutations in the viral NS3/4A protease has been well characterized, the mechanism for resistance of non-active site mutations is unclear. R155K and V36M often co-evolve and while R155K alters the electrostatic network at the binding site, V36M is more than 13 Angstrom away. In this study the mechanism by which V36M confers resistance, in the context of R155K, is elucidated with drug susceptibility assays, crystal structures, and molecular dynamics (MD) simulations for three protease inhibitors: telaprevir, boceprevir and danoprevir. The R155K and R155K ...


Orbit: A New Paradigm For Genetic Engineering Of Mycobacterial Chromosomes, Kenan C. Murphy, Samantha J. Nelson, Subhalaxmi Nambi, Kadamba Papavinasasundaram, Christina E. Baer, Christopher M. Sassetti Dec 2018

Orbit: A New Paradigm For Genetic Engineering Of Mycobacterial Chromosomes, Kenan C. Murphy, Samantha J. Nelson, Subhalaxmi Nambi, Kadamba Papavinasasundaram, Christina E. Baer, Christopher M. Sassetti

Open Access Articles

Two efficient recombination systems were combined to produce a versatile method for chromosomal engineering that obviates the need to prepare double-stranded DNA (dsDNA) recombination substrates. A synthetic "targeting oligonucleotide" is incorporated into the chromosome via homologous recombination mediated by the phage Che9c RecT annealase. This oligonucleotide contains a site-specific recombination site for the directional Bxb1 integrase (Int), which allows the simultaneous integration of a "payload plasmid" that contains a cognate recombination site and a selectable marker. The targeting oligonucleotide and payload plasmid are cotransformed into a RecT- and Int-expressing strain, and drug-resistant homologous recombinants are selected in a single step ...


General Decapping Activators Target Different Subsets Of Inefficiently Translated Mrnas, Feng He, Alper Celik, Chan Wu, Allan Jacobson Dec 2018

General Decapping Activators Target Different Subsets Of Inefficiently Translated Mrnas, Feng He, Alper Celik, Chan Wu, Allan Jacobson

Open Access Articles

The Dcp1-Dcp2 decapping enzyme and the decapping activators Pat1, Dhh1, and Lsm1 regulate mRNA decapping, but their mechanistic integration is unknown. We analyzed the gene expression consequences of deleting PAT1, LSM1, or DHH1, or the DCP2 C-terminal domain, and found that: i) the Dcp2 C-terminal domain is an effector of both negative and positive regulation; ii) rather than being global activators of decapping, Pat1, Lsm1, and Dhh1 directly target specific subsets of yeast mRNAs and loss of the functions of each of these factors has substantial indirect consequences for genome-wide mRNA expression; and iii) transcripts targeted by Pat1, Lsm1, and ...


Potent Cas9 Inhibition In Bacterial And Human Cells By Acriic4 And Acriic5 Anti-Crispr Proteins, Jooyoung Lee, Aamir Mir, Alireza Edraki, Bianca Garcia, Nadia Amrani, Hannah E. Lou, Ildar Gainetdinov, April Pawluk, Raed Ibraheim, Xin D. Gao, Pengpeng Liu, Alan R. Davidson, Karen L. Maxwell, Erik J. Sontheimer Dec 2018

Potent Cas9 Inhibition In Bacterial And Human Cells By Acriic4 And Acriic5 Anti-Crispr Proteins, Jooyoung Lee, Aamir Mir, Alireza Edraki, Bianca Garcia, Nadia Amrani, Hannah E. Lou, Ildar Gainetdinov, April Pawluk, Raed Ibraheim, Xin D. Gao, Pengpeng Liu, Alan R. Davidson, Karen L. Maxwell, Erik J. Sontheimer

Open Access Articles

In their natural settings, CRISPR-Cas systems play crucial roles in bacterial and archaeal adaptive immunity to protect against phages and other mobile genetic elements, and they are also widely used as genome engineering technologies. Previously we discovered bacteriophage-encoded Cas9-specific anti-CRISPR (Acr) proteins that serve as countermeasures against host bacterial immunity by inactivating their CRISPR-Cas systems (A. Pawluk, N. Amrani, Y. Zhang, B. Garcia, et al., Cell 167:1829-1838.e9, 2016, https://doi.org/10.1016/j.cell.2016.11.017). We hypothesized that the evolutionary advantages conferred by anti-CRISPRs would drive the widespread occurrence of these proteins in nature (K ...


Deciphering The Molecular Basis Of Mycobacteria And Lipoglycan Recognition By The C-Type Lectin Dectin-2, Alexiane Decout, Devinder Kaur, Jerome Nigou Nov 2018

Deciphering The Molecular Basis Of Mycobacteria And Lipoglycan Recognition By The C-Type Lectin Dectin-2, Alexiane Decout, Devinder Kaur, Jerome Nigou

Open Access Articles

Dectin-2 is a C-type lectin involved in the recognition of several pathogens such as Aspergillus fumigatus, Candida albicans, Schistosoma mansonii, and Mycobacterium tuberculosis that triggers Th17 immune responses. Identifying pathogen ligands and understanding the molecular basis of their recognition is one of the current challenges. Purified M. tuberculosis mannose-capped lipoarabinomannan (ManLAM) was shown to induce signaling via Dectin-2, an activity that requires the (alpha1 --> 2)-linked mannosides forming the caps. Here, using isogenic M. tuberculosis mutant strains, we demonstrate that ManLAM is a bona fide and actually the sole ligand mediating bacilli recognition by Dectin-2, although M. tuberculosis produces a ...


Development Of A Pd-L1 Pet Imaging Biomarker, Caleb Jack Bridgwater Nov 2018

Development Of A Pd-L1 Pet Imaging Biomarker, Caleb Jack Bridgwater

Posters-at-the-Capitol

Immunotherapy strategies are very promising treatments for cancer patients. Specifically, Immune checkpoint inhibitor therapy focusing on the PD-1/PD-L1 pathway shows long-lasting positive results in many cancer patients. Unfortunately, not all the patients can benefit from this highly effective treatment. Hence, there is a great need for predictive biomarkers. Immunohistochemical (IHC) staining has been used as a way of predicting patient response, yet shows many problems. For example, IHC utilizes an invasive biopsy and sample fixing, which creates an incomplete and delayed picture of the patient’s biochemistry and the tumor microenvironment, consequently ignoring metastases.

The purpose of this study ...


Signaling Pathways Induced By Leptin During Epithelial(-)Mesenchymal Transition In Breast Cancer, Monserrat Olea-Flores, Juan Carlos Juarez-Cruz, Miguel A. Mendoza-Catalan, Teresita Padilla-Benavides, Napoleon Navarro-Tito Nov 2018

Signaling Pathways Induced By Leptin During Epithelial(-)Mesenchymal Transition In Breast Cancer, Monserrat Olea-Flores, Juan Carlos Juarez-Cruz, Miguel A. Mendoza-Catalan, Teresita Padilla-Benavides, Napoleon Navarro-Tito

Open Access Articles

Leptin is an adipokine that is overexpressed in obese and overweight people. Interestingly, women with breast cancer present high levels of leptin and of its receptor ObR. Leptin plays an important role in breast cancer progression due to the biological processes it participates in, such as epithelial(-)mesenchymal transition (EMT). EMT consists of a series of orchestrated events in which cell(-)cell and cell(-)extracellular matrix interactions are altered and lead to the release of epithelial cells from the surrounding tissue. The cytoskeleton is also re-arranged, allowing the three-dimensional movement of epithelial cells into the extracellular matrix. This transition provides ...


Rare Gene Fusion Rearrangement Sptnb1-Pdgfrb In An Atypical Myeloproliferative Neoplasm, Vanessa Fiorini Furtado, Neeraj Y. Saini, William V. Walsh, Venu G. Bathini, Patricia M. Miron Oct 2018

Rare Gene Fusion Rearrangement Sptnb1-Pdgfrb In An Atypical Myeloproliferative Neoplasm, Vanessa Fiorini Furtado, Neeraj Y. Saini, William V. Walsh, Venu G. Bathini, Patricia M. Miron

Open Access Articles

The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia recognizes a distinct class of myeloid and lymphoid tumors with eosinophilia-related proliferations associated with specific gene rearrangements, one of which involves rearrangements of platelet-derived growth factor receptor B (PDGFRB) gene. We report a case of a rare PDGFRB rearrangement with SPTNB1 (spectrin beta, nonerythrocytic 1) that presented as atypical myeloproliferative neoplasm.


Histone Citrullination Represses Mirna Expression Resulting In Increased Oncogene Mrnas In Somatolactotrope Cells., Stanley B Devore, Coleman H. Young, Guangyuan Li, Anitha Sundararajan, Thiruvarangan Ramaraj, Joann Mudge, Faye Schilkey, Aaron Muth, Paul R. Thompson, Brian D. Cherrington Sep 2018

Histone Citrullination Represses Mirna Expression Resulting In Increased Oncogene Mrnas In Somatolactotrope Cells., Stanley B Devore, Coleman H. Young, Guangyuan Li, Anitha Sundararajan, Thiruvarangan Ramaraj, Joann Mudge, Faye Schilkey, Aaron Muth, Paul R. Thompson, Brian D. Cherrington

University of Massachusetts Medical School Publications

Peptidylarginine deiminase (PAD) enzymes convert histone arginine residues into citrulline to modulate chromatin organization and gene expression. Although PADs are expressed in anterior pituitary gland cells, their functional role and expression in pituitary adenomas is unknown. To begin to address these questions, we first examined normal human pituitaries and pituitary adenomas and found that PAD2, PAD4 and citrullinated histones are highest in prolactinomas and somatoprolactinomas. In the somatoprolactinoma-derived GH3 cell line, PADs citrullinate histone H3, which is attenuated by a pan-PAD inhibitor. RNA-sequencing and ChIP studies show that the expression of microRNAs let-7c-2, miR-23b and miR-29c is suppressed by histone ...


The N-Terminal Methyltransferase Homologs Nrmt1 And Nrmt2 Exhibit Novel Regulation Of Activity Through Heterotrimer Formation., Jon David Faughn Aug 2018

The N-Terminal Methyltransferase Homologs Nrmt1 And Nrmt2 Exhibit Novel Regulation Of Activity Through Heterotrimer Formation., Jon David Faughn

Electronic Theses and Dissertations

Protein, DNA, and RNA methyltransferases have an ever-expanding list of novel substrates and catalytic activities. Even within families and between homologs, it is becoming clear the intricacies of methyltransferase specificity and regulation are far more diverse than originally thought. In addition to specific substrates and distinct methylation levels, methyltransferase activity can be altered through formation of complexes with close homologs. This work involves the N-terminal methyltransferase homologs NRMT1 and NRMT2. NRMT1 is a ubiquitously expressed distributive trimethylase. NRMT2 is a monomethylase expressed at low levels and in a tissue-specific manner. They are both nuclear methyltransferases with overlapping target consensus sequences ...


Rna Binding Proteins Co-Localize With Small Tau Inclusions In Tauopathy, Brandon F. Maziuk, Daniel J. Apicco, Anna Lourdes Cruz, Lulu Jiang, Peter E. A. Ash, Edroaldo Lummertz. Da Rocha, Cheng Zhang, Wai Haung Yu, John D. Leszyk, Jose F. Abisambra, Hu Li, Benjamin Wolozin Aug 2018

Rna Binding Proteins Co-Localize With Small Tau Inclusions In Tauopathy, Brandon F. Maziuk, Daniel J. Apicco, Anna Lourdes Cruz, Lulu Jiang, Peter E. A. Ash, Edroaldo Lummertz. Da Rocha, Cheng Zhang, Wai Haung Yu, John D. Leszyk, Jose F. Abisambra, Hu Li, Benjamin Wolozin

Open Access Articles

The development of insoluble, intracellular neurofibrillary tangles composed of the microtubule-associated protein tau is a defining feature of tauopathies, including Alzheimer's disease (AD). Accumulating evidence suggests that tau pathology co-localizes with RNA binding proteins (RBPs) that are known markers for stress granules (SGs). Here we used proteomics to determine how the network of tau binding proteins changes with disease in the rTg4510 mouse, and then followed up with immunohistochemistry to identify RNA binding proteins that co-localize with tau pathology. The tau interactome networks revealed striking disease-related changes in interactions between tau and a multiple RBPs, and biochemical fractionation studies ...


Llc Tumor Cells-Derivated Factors Reduces Adipogenesis In Co-Culture System, Magno Alves Lopes, Felipe Oliveira Franco, Felipe Henriques, Sidney Barnabe Peres, Miguel Luiz Batista Jr. Jul 2018

Llc Tumor Cells-Derivated Factors Reduces Adipogenesis In Co-Culture System, Magno Alves Lopes, Felipe Oliveira Franco, Felipe Henriques, Sidney Barnabe Peres, Miguel Luiz Batista Jr.

Open Access Articles

Cancer cachexia (CC) is a multifactorial syndrome with an unknown etiology. The primary symptom is the progressive reduction of the body weight. Recently, down-regulation of adipogenic and lipogenic genes were demonstrated to be early affected during cachexia progression in adipose tissue (AT), resulting in AT remodeling. Thus, this study aimed to evaluate in a co-culture system the influence of the Lewis Lung Carcinoma (LLC) tumor cells (c/c-LLC) in an established pre-adipocyte cell line 3T3-L1 adipogenic capacity. c/c-LLC in the presence of 3T3-L1 caused a reduction in lipids accumulation, suggesting that secretory tumor cells products may affect adipogenesis. Interestingly ...


Neurexin Directs Partner-Specific Synaptic Connectivity In C. Elegans, Alison Philbrook, Shankar Ramachandran, Christopher M. Lambert, Devyn Oliver, Jeremy Florman, Mark J. Alkema, Michele Lemons, Michael M. Francis Jul 2018

Neurexin Directs Partner-Specific Synaptic Connectivity In C. Elegans, Alison Philbrook, Shankar Ramachandran, Christopher M. Lambert, Devyn Oliver, Jeremy Florman, Mark J. Alkema, Michele Lemons, Michael M. Francis

Open Access Articles

In neural circuits, individual neurons often make projections onto multiple postsynaptic partners. Here, we investigate molecular mechanisms by which these divergent connections are generated, using dyadic synapses in C. elegans as a model. We report that C. elegans nrx-1/neurexin directs divergent connectivity through differential actions at synapses with partnering neurons and muscles. We show that cholinergic outputs onto neurons are, unexpectedly, located at previously undefined spine-like protrusions from GABAergic dendrites. Both these spine-like features and cholinergic receptor clustering are strikingly disrupted in the absence of nrx-1. Excitatory transmission onto GABAergic neurons, but not neuromuscular transmission, is also disrupted. Our ...


Identification Of A Novel Invasion-Promoting Region In Insulin Receptor Substrate 2, Jose Mercado-Matos, Jenny Janusis, Sha Zhu, Samuel S. Chen, Leslie M. Shaw Jun 2018

Identification Of A Novel Invasion-Promoting Region In Insulin Receptor Substrate 2, Jose Mercado-Matos, Jenny Janusis, Sha Zhu, Samuel S. Chen, Leslie M. Shaw

University of Massachusetts Medical School Faculty Publications

Although the insulin receptor substrate (IRS) proteins IRS1 and IRS2 share considerable homology and activate common signaling pathways, their contributions to breast cancer are distinct. IRS1 has been implicated in the proliferation and survival of breast tumor cells. In contrast, IRS2 facilitates glycolysis, invasion, and metastasis. To determine the mechanistic basis for IRS2-dependent functions, we investigated unique structural features of IRS2 that are required for invasion. Our studies revealed that the ability of IRS2 to promote invasion is dependent upon upstream insulin-like growth factor 1 receptor (IGF-1R)/insulin receptor (IR) activation and the recruitment and activation of phosphatidylinositol 3-kinase (PI3K ...


Dynamics Of Human Protein Kinase Aurora A Linked To Drug Selectivity, Warintra Pitsawong, Vanessa Buosi, Renee Otten, Roman V. Agafonov, Adelajda Zorba, Nadja Kern, Steffen Kutter, Gunther Kern, Ricardo Ap Padua, Xavier Meniche, Dorothee Kern Jun 2018

Dynamics Of Human Protein Kinase Aurora A Linked To Drug Selectivity, Warintra Pitsawong, Vanessa Buosi, Renee Otten, Roman V. Agafonov, Adelajda Zorba, Nadja Kern, Steffen Kutter, Gunther Kern, Ricardo Ap Padua, Xavier Meniche, Dorothee Kern

Open Access Articles

Protein kinases are major drug targets, but the development of highly-selective inhibitors has been challenging due to the similarity of their active sites. The observation of distinct structural states of the fully-conserved Asp-Phe-Gly (DFG) loop has put the concept of conformational selection for the DFG-state at the center of kinase drug discovery. Recently, it was shown that Gleevec selectivity for the Tyr-kinase Abl was instead rooted in conformational changes after drug binding. Here, we investigate whether protein dynamics after binding is a more general paradigm for drug selectivity by characterizing the binding of several approved drugs to the Ser/Thr-kinase ...


Development Of Lc-Ms For The Identification And Characterization Of Non-Adjacent Dna Photoproduct Formation In G-Quadruplex Forming Sequences, Claudia Posadas May 2018

Development Of Lc-Ms For The Identification And Characterization Of Non-Adjacent Dna Photoproduct Formation In G-Quadruplex Forming Sequences, Claudia Posadas

Arts & Sciences Electronic Theses and Dissertations

Ultraviolet light is well known to induce cyclobutane pyrimidine dimers (CPD) and pyrimidine (6–4) pyrimidone photoproducts in duplex DNA, which interfere with DNA replication and transcription. Recently, a new class of DNA photoproducts known as anti cyclobutanepyrimidine dimers have been discovered, which form in G-quadruplex forming sequences in solution. G-quadruplex structures have been proposed to form in human DNA telomeres and certain promoters in vivo but evidence for their existence has been lacking. Since anti-cyclobutante pyrimidine dimers have been shown to form in G-quadruplex forming sequences, their formation in irradiated human cells could be used to confirm the ...


Substrate Sequence Selectivity Of Apobec3a Implicates Intra-Dna Interactions, Tania V. Silvas, Shurong Hou, Wazo Myint, Ellen A. Nalivaika, Mohan Somasundaran, Brian A. Kelch, Hiroshi Matsuo, Nese Kurt Yilmaz, Celia A. Schiffer May 2018

Substrate Sequence Selectivity Of Apobec3a Implicates Intra-Dna Interactions, Tania V. Silvas, Shurong Hou, Wazo Myint, Ellen A. Nalivaika, Mohan Somasundaran, Brian A. Kelch, Hiroshi Matsuo, Nese Kurt Yilmaz, Celia A. Schiffer

Open Access Articles

The APOBEC3 (A3) family of human cytidine deaminases is renowned for providing a first line of defense against many exogenous and endogenous retroviruses. However, the ability of these proteins to deaminate deoxycytidines in ssDNA makes A3s a double-edged sword. When overexpressed, A3s can mutate endogenous genomic DNA resulting in a variety of cancers. Although the sequence context for mutating DNA varies among A3s, the mechanism for substrate sequence specificity is not well understood. To characterize substrate specificity of A3A, a systematic approach was used to quantify the affinity for substrate as a function of sequence context, length, secondary structure, and ...


All-In-One Adeno-Associated Virus Delivery And Genome Editing By Neisseria Meningitidis Cas9 In Vivo, Raed Ibraheim, Chun-Qing Song, Aamir Mir, Nadia Amrani, Wen Xue, Erik J. Sontheimer May 2018

All-In-One Adeno-Associated Virus Delivery And Genome Editing By Neisseria Meningitidis Cas9 In Vivo, Raed Ibraheim, Chun-Qing Song, Aamir Mir, Nadia Amrani, Wen Xue, Erik J. Sontheimer

University of Massachusetts Medical School Faculty Publications

Clustered, regularly interspaced, short palindromic repeats (CRISPR) and CRISPR-associated proteins (Cas) have recently opened a new avenue for gene therapy. Cas9 nuclease guided by a single-guide RNA (sgRNA) has been extensively used for genome editing. Currently, three Cas9 orthologs have been adapted forin vivo genome engineering applications: SpyCas9, SauCas9 and CjeCas9. However, additional in vivo editing platforms are needed, in part to enable a greater range of sequences to be accessed via viral vectors, especially those in which Cas9 and sgRNA are combined into a single vector genome. Here, we present an additional in vivo editing platform using Neisseria ...


Nmecas9 Is An Intrinsically High-Fidelity Genome Editing Platform, Nadia Amrani, Xin D. Gao, Pengpeng Liu, Alireza Edraki, Aamir Mir, Raed Ibraheim, Ankit Gupta, Kanae E. Sasaki, Tong Wu, Thomas G. Fazzio, Lihua Julie Zhu, Scot A. Wolfe, Erik J. Sontheimer May 2018

Nmecas9 Is An Intrinsically High-Fidelity Genome Editing Platform, Nadia Amrani, Xin D. Gao, Pengpeng Liu, Alireza Edraki, Aamir Mir, Raed Ibraheim, Ankit Gupta, Kanae E. Sasaki, Tong Wu, Thomas G. Fazzio, Lihua Julie Zhu, Scot A. Wolfe, Erik J. Sontheimer

University of Massachusetts Medical School Faculty Publications

Background: The development of CRISPR genome editing has transformed biomedical research. Most applications reported thus far rely upon the Cas9 protein from Streptococcus pyogenes SF370 (SpyCas9). With many RNA guides, wild-type SpyCas9 can induce significant levels of unintended mutations at near-cognate sites, necessitating substantial efforts toward the development of strategies to minimize off-target activity. Although the genome-editing potential of thousands of other Cas9 orthologs remains largely untapped, it is not known how many will require similarly extensive engineering to achieve single-site accuracy within large (e.g. mammalian) genomes. In addition to its off-targeting propensity, SpyCas9 is encoded by a relatively ...


The Regulation Of Dna Methylation In Mammalian Development And Cancer, Nicolas Veland May 2018

The Regulation Of Dna Methylation In Mammalian Development And Cancer, Nicolas Veland

UT GSBS Dissertations and Theses (Open Access)

DNA methylation is an essential epigenetic modification in mammals, as it plays important regulatory roles in multiple biological processes, such as gene transcription, maintenance of chromosomal structure and genomic stability, genomic imprinting, retrotransposon silencing, and X-chromosome inactivation. Dysregulation of DNA methylation is associated with various human diseases. For example, cancer cells usually show global hypomethylation and regional hypermenthylation, which have been implicated in genomic instability and tumor suppressor silencing, respectively. Although great progress has been made in elucidating the biological functions of DNA methylation over the last several decades, how DNA methylation patterns and levels are regulated and dysregulated is ...


Role Of Protein Charge Density On Hepatitis B Virus Capsid Formation, Xinyu Sun, Dong Li, Zhaoshuai Wang, Panchao Yin, Rundong Hu, Rundong Hu, Hui Li, Qiao Liu, Yunyi Gao, Baiping Ren, Jie Zheng, Yinan Wei, Tianbo Liu Apr 2018

Role Of Protein Charge Density On Hepatitis B Virus Capsid Formation, Xinyu Sun, Dong Li, Zhaoshuai Wang, Panchao Yin, Rundong Hu, Rundong Hu, Hui Li, Qiao Liu, Yunyi Gao, Baiping Ren, Jie Zheng, Yinan Wei, Tianbo Liu

Chemistry Faculty Publications

The role of electrostatic interactions in the viral capsid assembly process was studied by comparing the assembly process of a truncated hepatitis B virus capsid protein Cp149 with its mutant protein D2N/D4N, which has the same conformational structure but four fewer charges per dimer. The capsid protein self-assembly was investigated under a wide range of protein surface charge densities by changing the protein concentration, buffer pH, and solution ionic strength. Lowering the protein charge density favored the capsid formation. However, lowering charge beyond a certain point resulted in capsid aggregation and precipitation. Interestingly, both the wild-type and D2N/D4N ...


Jip1-Mediated Jnk Activation Negatively Regulates Synaptic Plasticity And Spatial Memory, Caroline Morel, Tessi Sherrin, Norman J. Kennedy, Kelly H. Forest, Seda Barutcu, Michael Robles, Ezekiel Carpenter-Hyland, Naghum Alfulaij, Claire L. Standen, Robert A. Nichols, Morris Benveniste, Roger J. Davis, Cedomir Todorovic Apr 2018

Jip1-Mediated Jnk Activation Negatively Regulates Synaptic Plasticity And Spatial Memory, Caroline Morel, Tessi Sherrin, Norman J. Kennedy, Kelly H. Forest, Seda Barutcu, Michael Robles, Ezekiel Carpenter-Hyland, Naghum Alfulaij, Claire L. Standen, Robert A. Nichols, Morris Benveniste, Roger J. Davis, Cedomir Todorovic

University of Massachusetts Medical School Faculty Publications

The c-Jun N-terminal kinase (JNK) signal transduction pathway is implicated in learning and memory. Here, we examined the role of JNK activation mediated by the JIP1 scaffold protein. We compared male wild-type mice with a mouse model harboring a point mutation in the Jip1 gene that selectively blocks JIP1-mediated JNK activation. These male mutant mice exhibited increased NMDA receptor currents, increased NMDA receptor-mediated gene expression, and a lower threshold for induction of hippocampal long-term potentiation. The JIP1 mutant mice also displayed improved hippocampus-dependent spatial memory and enhanced associative fear conditioning. These results were confirmed using a second JIP1 mutant mouse ...


Increased Liver Tumor Formation In Neutral Sphingomyelinase-2-Deficient Mice, Liansheng Zhong, Ji Na Kong, Michael B. Dinkins, Silvia Leanhart, Zhihui Zhu, Stefka D. Spassieva, Haiyan Qin, Hsuan-Pei Lin, Ahmed Elsherbini, Rebecca Wang, Xue Jiang, Mariana N. Nikolova‑Karakashian, Guanghu Wang, Erhard Bieberich Mar 2018

Increased Liver Tumor Formation In Neutral Sphingomyelinase-2-Deficient Mice, Liansheng Zhong, Ji Na Kong, Michael B. Dinkins, Silvia Leanhart, Zhihui Zhu, Stefka D. Spassieva, Haiyan Qin, Hsuan-Pei Lin, Ahmed Elsherbini, Rebecca Wang, Xue Jiang, Mariana N. Nikolova‑Karakashian, Guanghu Wang, Erhard Bieberich

Physiology Faculty Publications

Sphingolipids are key signaling lipids in cancer. Genome-wide studies have identified neutral SMase-2 (nSMase2), an enzyme generating ceramide from SM, as a potential repressor for hepatocellular carcinoma. However, little is known about the sphingolipids regulated by nSMase2 and their roles in liver tumor development. We discovered growth of spontaneous liver tumors in 27.3% (9 of 33) of aged male nSMase2-deficient (fro/fro) mice. Lipidomics analysis showed a marked increase of SM in the tumor. Unexpectedly, tumor tissues presented with more than a 7-fold increase of C16-ceramide, concurrent with upregulation of ceramide synthase 5. The fro/fro liver ...


Biochemical Analysis Of Dimethyl Suberimidate-Crosslinked Yeast Nucleosomes, Yuichi Ichikawa, Paul D. Kaufman Mar 2018

Biochemical Analysis Of Dimethyl Suberimidate-Crosslinked Yeast Nucleosomes, Yuichi Ichikawa, Paul D. Kaufman

Open Access Articles

Nucleosomes are the fundamental unit of eukaryotic chromosome packaging, comprised of 147 bp of DNA wrapped around two molecules of each of the core histone proteins H2A, H2B, H3, and H4. Nucleosomes are symmetrical, with one axis of symmetry centered on the homodimeric interaction between the C-termini of the H3 molecules. To explore the functional consequences of nucleosome symmetry, we designed an obligate pair of H3 heterodimers, termed H3X and H3Y, allowing us to compare cells with single or double H3 alterations. Our biochemical validation of the heterodimeric X-Y interaction included intra-nucleosomal H3 crosslinking using dimethyl suberimidate (DMS). Here, we ...