Life Sciences Commons^™

Human Metapneumovirus Induces Formation Of Inclusion Bodies For Efficient Genome Replication And Transcription, Nicolás P. Cifuentes-Muñoz, Jean Branttie, Kerri Beth Slaughter, Rebecca Ellis Dutch

Molecular and Cellular Biochemistry Faculty Publications

Human metapneumovirus (HMPV) causes significant upper and lower respiratory disease in all age groups worldwide. The virus possesses a negative-sense single-stranded RNA genome of approximately 13.3 kb encapsidated by multiple copies of the nucleoprotein (N), giving rise to helical nucleocapsids. In addition, copies of the phosphoprotein (P) and the large RNA polymerase (L) decorate the viral nucleocapsids. After viral attachment, endocytosis, and fusion mediated by the viral glycoproteins, HMPV nucleocapsids are released into the cell cytoplasm. To visualize the subsequent steps of genome transcription and replication, a fluorescence in situ hybridization (FISH) protocol was established to detect different viral RNA …

Mutations In The Transmembrane Domain And Cytoplasmic Tail Of Hendra Virus Fusion Protein Disrupt Virus-Like-Particle Assembly, Nicolás P. Cifuentes-Muñoz, Weina Sun, Greeshma Ray, Phuong Tieu Schmitt, Stacy Webb, Kathleen Gibson, Rebecca Ellis Dutch, Anthony P. Schmitt

Molecular and Cellular Biochemistry Faculty Publications

Hendra virus (HeV) is a zoonotic paramyxovirus that causes deadly illness in horses and humans. An intriguing feature of HeV is the utilization of endosomal protease for activation of the viral fusion protein (F). Here we investigated how endosomal F trafficking affects HeV assembly. We found that the HeV matrix (M) and F proteins each induced particle release when they were expressed alone but that their coexpression led to coordinated assembly of virus-like particles (VLPs) that were morphologically and physically distinct from M-only or F-only VLPs. Mutations to the F protein transmembrane domain or cytoplasmic tail that disrupted endocytic trafficking …

Quantitative Mass Spectrometry Reveals Changes In Histone H2b Variants As Cells Undergo Inorganic Arsenic-Mediated Cellular Transformation, Matthew Rea, Tingting Jiang, Rebekah Eleazer, Meredith Eckstein, Alan G. Marshall, Yvonne N. Fondufe-Mittendorf

Molecular and Cellular Biochemistry Faculty Publications

Exposure to inorganic arsenic, a ubiquitous environmental toxic metalloid, leads to carcinogenesis. However, the mechanism is unknown. Several studies have shown that inorganic arsenic exposure alters specific gene expression patterns, possibly through alterations in chromatin structure. While most studies on understanding the mechanism of chromatin-mediated gene regulation have focused on histone post-translational modifications, the role of histone variants remains largely unknown. Incorporation of histone variants alters the functional properties of chromatin. To understand the global dynamics of chromatin structure and function in arsenic-mediated carcinogenesis, analysis of the histone variants incorporated into the nucleosome and their covalent modifications is required. Here …

Transcriptional Activity Of The Islet Β Cell Factor Pdx1 Is Augmented By Lysine Methylation Catalyzed By The Methyltransferase Set7/9, Aarthi V. Maganti, Bernhard Maier, Sarah A. Tersey, Megan L. Sampley, Amber L. Mosley, Sabire Özcan, Boobalan Pachaiyappan, Patrick M. Woster, Chad S. Hunter, Roland Stein, Raghavendra G. Mirmira

Molecular and Cellular Biochemistry Faculty Publications

The transcription factor Pdx1 is crucial to islet β cell function and regulates target genes in part through interaction with coregulatory factors. Set7/9 is a Lys methyltransferase that interacts with Pdx1. Here we tested the hypothesis that Lys methylation of Pdx1 by Set7/9 augments Pdx1 transcriptional activity. Using mass spectrometry and mutational analysis of purified proteins, we found that Set7/9 methylates the N-terminal residues Lys-123 and Lys-131 of Pdx1. Methylation of these residues occurred only in the context of intact, full-length Pdx1, suggesting a specific requirement of secondary and/or tertiary structural elements for catalysis by Set7/9. Immunoprecipitation assays and mass …

Analysis Of Cathepsin And Furin Proteolytic Enzymes Involved In Viral Fusion Protein Activation In Cells Of The Bat Reservoir Host, Farah El Najjar, Levi Lampe, Michelle L. Baker, Lin-Fa Wang, Rebecca Ellis Dutch

Molecular and Cellular Biochemistry Faculty Publications

Bats of different species play a major role in the emergence and transmission of highly pathogenic viruses including Ebola virus, SARS-like coronavirus and the henipaviruses. These viruses require proteolytic activation of surface envelope glycoproteins needed for entry, and cellular cathepsins have been shown to be involved in proteolysis of glycoproteins from these distinct virus families. Very little is currently known about the available proteases in bats. To determine whether the utilization of cathepsins by bat-borne viruses is related to the nature of proteases in their natural hosts, we examined proteolytic processing of several viral fusion proteins in cells derived from …

Sudemycin E Influences Alternative Splicing And Changes Chromatin Modifications, Paolo Convertini, Manli Shen, Philip M. Potter, Gustavo Palacios, Chandraiah Lagisetti, Pierre De La Grange, Craig Horbinski, Yvonne N. Fondufe-Mittendorf, Thomas R. Webb, Stefan Stamm

Molecular and Cellular Biochemistry Faculty Publications

Sudemycin E is an analog of the pre-messenger RNA splicing modulator FR901464 and its derivative spliceostatin A. Sudemycin E causes the death of cancer cells through an unknown mechanism. We found that similar to spliceostatin A, sudemycin E binds to the U2 small nuclear ribonucleoprotein (snRNP) component SF3B1. Native chromatin immunoprecipitations showed that U2 snRNPs physically interact with nucleosomes. Sudemycin E induces a dissociation of the U2 snRNPs and decreases their interaction with nucleosomes. To determine the effect on gene expression, we performed genome-wide array analysis. Sudemycin E first causes a rapid change in alternative pre-messenger RNA splicing, which is …

Controls Of Nucleosome Positioning In The Human Genome, Daniel J. Gaffney, Graham Mcvicker, Athma A. Pai, Yvonne N. Fondufe-Mittendorf, Noah Lewellen, Katelyn Michelini, Jonathan Widom, Yoav Gilad, Jonathan K. Pritchard

Molecular and Cellular Biochemistry Faculty Publications

Nucleosomes are important for gene regulation because their arrangement on the genome can control which proteins bind to DNA. Currently, few human nucleosomes are thought to be consistently positioned across cells; however, this has been difficult to assess due to the limited resolution of existing data. We performed paired-end sequencing of micrococcal nuclease-digested chromatin (MNase-seq) from seven lymphoblastoid cell lines and mapped over 3.6 billion MNase-seq fragments to the human genome to create the highest-resolution map of nucleosome occupancy to date in a human cell type. In contrast to previous results, we find that most nucleosomes have more consistent positioning …

Cysteine 904 Is Required For Maximal Insulin Degrading Enzyme Activity And Polyanion Activation, Eun Suk Song, Manana Melikishvili, Michael G. Fried, Maria A. Juliano, Luiz Juliano, David W. Rodgers, Louis B. Hersh

Molecular and Cellular Biochemistry Faculty Publications

Cysteine residues in insulin degrading enzyme have been reported as non-critical for its activity. We found that converting the twelve cysteine residues in rat insulin degrading enzyme (IDE) to serines resulted in a cysteine-free form of the enzyme with reduced activity and decreased activation by polyanions. Mutation of each cysteine residue individually revealed cysteine 904 as the key residue required for maximal activity and polyanion activation, although other cysteines affect polyanion binding to a lesser extent. Based on the structure of IDE, Asn 575 was identified as a potential hydrogen bond partner for Cys904 and mutation of this residue also …

Prostate Cancer-Specific And Potent Antitumor Effect Of A Dd3-Controlled Oncolytic Virus Harboring The Pten Gene, Miao Ding, Xin Cao, Hai-Neng Xu, Jun-Kai Fan, Hong-Ling Huang, Dong-Qin Yang, Yu-Hua Li, Jian Wang, Runsheng Li, Xin-Yuan Liu

Molecular and Cellular Biochemistry Faculty Publications

Prostate cancer is a major health problem for men in Western societies. Here we report a Prostate Cancer-Specific Targeting Gene-Viro-Therapy (CTGVT-PCa), in which PTEN was inserted into a DD3-controlled oncolytic viral vector (OV) to form Ad.DD3.E1A.E1B(Δ55)-(PTEN) or, briefly, Ad.DD3.D55-PTEN. The woodchuck post-transcriptional element (WPRE) was also introduced at the downstream of the E1A coding sequence, resulting in much higher expression of the E1A gene. DD3 is one of the most prostate cancer-specific genes and has been used as a clinical bio-diagnostic marker. PTEN is frequently inactivated in primary prostate cancers, which is crucial for prostate cancer progression. Therefore, the Ad.DD3.D55-PTEN …

G9a Interacts With Snail And Is Critical For Snail-Mediated E-Cadherin Repression In Human Breast Cancer, Chenfang Dong, Yadi Wu, Jun Yao, Yifan Wang, Yinhua Yu, Piotr G. Rychahou, B. Mark Evers, Binhua P. Zhou

Molecular and Cellular Biochemistry Faculty Publications

Breast cancers are highly heterogeneous but can be grouped into subtypes based on several criteria, including level of expression of certain markers. Claudin-low breast cancer (CLBC) is associated with early metastasis and resistance to chemotherapy, while gene profiling indicates it is characterized by the expression of markers of epithelial-mesenchymal transition (EMT) - a phenotypic conversion linked with metastasis. Although the epigenetic program controlling the phenotypic and cellular plasticity of EMT remains unclear, one contributor may be methylation of the E-cadherin promoter, resulting in decreased E-cadherin expression, a hallmark of EMT. Indeed, reduced E-cadherin often occurs in CLBC and may contribute …

Activation Of Β-Catenin And Akt Pathways By Twist Are Critical For The Maintenance Of Emt Associated Cancer Stem Cell-Like Characters, Junlin Li, Binhua P. Zhou

Molecular and Cellular Biochemistry Faculty Publications

BACKGROUND: Epithelial-mesenchymal transition (EMT) not only confers tumor cells with a distinct advantage for metastatic dissemination, but also it provides those cells with cancer stem cell-like characters for proliferation and drug resistance. However, the molecular mechanism for maintenance of these stem cell-like traits remains unclear.

METHODS: In this study, we induced EMT in breast cancer MCF7 and cervical cancer Hela cells with expression of Twist, a key transcriptional factor of EMT. The morphological changes associated with EMT were analyzed by immunofluorescent staining and Western blotting. The stem cell-like traits associated with EMT were determined by tumorsphere-formation and expression of ALDH1 …

Pre-Mrna Secondary Structures Influence Exon Recognition, Michael Hiller, Zhaiyi Zhang, Rolf Backofen, Stefan Stamm

Molecular and Cellular Biochemistry Faculty Publications

The secondary structure of a pre-mRNA influences a number of processing steps including alternative splicing. Since most splicing regulatory proteins bind to single-stranded RNA, the sequestration of RNA into double strands could prevent their binding. Here, we analyzed the secondary structure context of experimentally determined splicing enhancer and silencer motifs in their natural pre-mRNA context. We found that these splicing motifs are significantly more single-stranded than controls. These findings were validated by transfection experiments, where the effect of enhancer or silencer motifs on exon skipping was much more pronounced in single-stranded conformation. We also found that the structural context of …

Induction Of Insulin Secretion In Engineered Liver Cells By Nitric Oxide, Latha Muniappan, Sabire Özcan

Molecular and Cellular Biochemistry Faculty Publications

BACKGROUND: Type 1 Diabetes Mellitus results from an autoimmune destruction of the pancreatic beta cells, which produce insulin. The lack of insulin leads to chronic hyperglycemia and secondary complications, such as cardiovascular disease. The currently approved clinical treatments for diabetes mellitus often fail to achieve sustained and optimal glycemic control. Therefore, there is a great interest in the development of surrogate beta cells as a treatment for type 1 diabetes. Normally, pancreatic beta cells produce and secrete insulin only in response to increased blood glucose levels. However in many cases, insulin secretion from non-beta cells engineered to produce insulin occurs …

Tsc2 Modulates Actin Cytoskeleton And Focal Adhesion Through Tsc1-Binding Domain And The Rac1 Gtpase, Elena Goncharova, Dmitry Goncharov, Daniel J. Noonan, Vera P Krymskaya

Molecular and Cellular Biochemistry Faculty Publications

Tuberous sclerosis complex (TSC) 1 and TSC2 are thought to be involved in protein translational regulation and cell growth, and loss of their function is a cause of TSC and lymphangioleiomyomatosis (LAM). However, TSC1 also activates Rho and regulates cell adhesion. We found that TSC2 modulates actin dynamics and cell adhesion and the TSC1-binding domain (TSC2-HBD) is essential for this function of TSC2. Expression of TSC2 or TSC2-HBD in TSC2-/- cells promoted Rac1 activation, inhibition of Rho, stress fiber disassembly, and focal adhesion remodeling. The down-regulation of TSC1 with TSC1 siRNA in TSC2-/- cells activated Rac1 and induced loss of …

The Snare Machinery Is Involved In Apical Plasma Membrane Trafficking In Mdck Cells, Seng Hui Low, Steven J. Chapin, Christian Wimmer, Sidney W. Whiteheart, László G. Kömüves, Keith E. Mostov, Thomas Weimbs

Molecular and Cellular Biochemistry Faculty Publications

We have investigated the controversial involvement of components of the SNARE (soluble N-ethyl maleimide–sensitive factor [NSF] attachment protein [SNAP] receptor) machinery in membrane traffic to the apical plasma membrane of polarized epithelial (MDCK) cells. Overexpression of syntaxin 3, but not of syntaxins 2 or 4, caused an inhibition of TGN to apical transport and apical recycling, and leads to an accumulation of small vesicles underneath the apical plasma membrane. All other tested transport steps were unaffected by syntaxin 3 overexpression. Botulinum neurotoxin E, which cleaves SNAP-23, and antibodies against α-SNAP inhibit both TGN to apical and basolateral transport in …