Cell Biology Commons^™

Genetic And Molecular Analysis Of Phytochromes From The Filamentous Fungus Neurospora Crassa, Allan C. Froehlich, Bosl Noh, Richard D. Vierstra, Jennifer Loros, Jay C. Dunlap

Dartmouth Scholarship

Phytochromes (Phys) comprise a superfamily of red-/far-red-light-sensing proteins. Whereas higher-plant Phys that control numerous growth and developmental processes have been well described, the biochemical characteristics and functions of the microbial forms are largely unknown. Here, we describe analyses of the expression, regulation, and activities of two Phys in the filamentous fungus Neurospora crassa. In addition to containing the signature N-terminal domain predicted to covalently associate with a bilin chromophore, PHY-1 and PHY-2 contain C-terminal histidine kinase and response regulator motifs, implying that they function as hybrid two-component sensor kinases activated by light. A bacterially expressed N-terminal fragment of PHY-2 covalently …

Empirical Analysis Of The Str Profiles Resulting From Conceptual Mixtures, David R. Paoletti, Travis E. Doom, Carissa M. Krane, Michael L. Raymer, Dan E. Krane

Biology Faculty Publications

Samples containing DNA from two or more individuals can be difficult to interpret. Even ascertaining the number of contributors can be challenging and associated uncertainties can have dramatic effects on the interpretation of testing results. Using an FBI genotypes dataset, containing complete genotype information from the 13 Combined DNA Index System (CODIS) loci for 959 individuals, all possible mixtures of three individuals were exhaustively and empirically computed. Allele sharing between pairs of individuals in the original dataset, a randomized dataset and datasets of generated cousins and siblings was evaluated as were the number of loci that were necessary to reliably …

Atypical Pkciota Contributes To Poor Prognosis Through Loss Of Apical-Basal Polarity And Cyclin E Overexpression In Ovarian Cancer, Astrid M. Eder, Xiaomei Sui, Daniel G. Rosen, Laura K. Nolden, Kwai Wa Cheng, John P. Lahad, Madhuri Kango-Singh, Karen H. Lu, Carla L. Warneke, Edward N. Atkinson, Isabelle Bedrosian, Khandan Keyomarsi, Wen-Lin Kuo, Joe W. Gray, Jerry C. P. Yin, Jinsong Liu, Georg Halder, Gordon B. Mills

Biology Faculty Publications

We show that atypical PKCι, which plays a critical role in the establishment and maintenance of epithelial cell polarity, is genomically amplified and overexpressed in serous epithelial ovarian cancers. Furthermore, PKCι protein is markedly increased or mislocalized in all serous ovarian cancers. An increased PKCι DNA copy number is associated with decreased progression-free survival in serous epithelial ovarian cancers. In a Drosophila in vivo epithelial tissue model, overexpression of persistently active atypical PKC results in defects in apical-basal polarity, increased Cyclin E protein expression, and increased proliferation. Similar to the Drosophila model, increased PKCι proteins levels are associated with …

Group 13 Hox Proteins Interact With The Mh2 Domain Of R-Smads And Modulate Smad Transcriptional Activation Functions Independent Of Hox Dna Binding Capability, Thomas M. Williams, Melissa E. Williams, Joanne H. Heaton, Thomas D. Gelehrter, Jeffrey W. Innis

Biology Faculty Publications

Interactions with co-factors provide a means by which HOX proteins exert specificity. To identify candidate protein interactors of HOXA13, we created and screened an E11.5–E12.5, distal limb bud yeast two-hybrid prey library. Among the interactors, we isolated the BMP-signaling effector Smad5, which interacted with the paralogous HOXD13 but not with HOXA11 or HOXA9, revealing unique interaction capabilities of the AbdB-like HOX proteins. Using deletion mutants, we determined that the MH2 domain of Smad5 is necessary for HOXA13 interaction.

This is the first report demonstrating an interaction between HOX proteins and the MH2 domain of Smad proteins. HOXA13 and HOXD13 …

Calmodulin And Pf6 Are Components Of A Complex That Localizes To The C1 Microtubule Of The Flagellar Central Apparatus, Matthew J. Wargo, Erin E. Dymek, Elizabeth F. Smith

Dartmouth Scholarship

Studies of flagellar motility in Chlamydomonas mutants lacking specific central apparatus components have supported the hypothesis that the inherent asymmetry of this structure provides important spatial cues for asymmetric regulation of dynein activity. These studies have also suggested that specific projections associated with the C1 and C2 central tubules make unique contributions to modulating motility; yet, we still do not know the identities of most polypeptides associated with the central tubules. To identify components of the C1a projection, we took an immunoprecipitation approach using antibodies generated against PF6. The pf6 mutant lacks the C1a projection and possesses flagella that only …

Myod Targets Chromatin Remodeling Complexes To The Myogenin Locus Prior To Forming A Stable Dna-Bound Complex, Ivana L. De La Serna, Yasuyuki Ohkawa, Charlotte A. Berkes, Donald A. Bergstrom, Caroline S. Dacwag, Stephen J. Tapscott Fred Hutchinson Cancer Research Center, Anthony N. Imbalzano

Biology Faculty Publications

The activation of muscle-specific gene expression requires the coordinated action of muscle regulatory proteins and chromatin-remodeling enzymes. Microarray analysis performed in the presence or absence of a dominant-negative BRG1 ATPase demonstrated that approximately one-third of MyoD-induced genes were highly dependent on SWI/SNF enzymes. To understand the mechanism of activation, we performed chromatin immunoprecipitations analyzing the myogenin promoter. We found that H4 hyperacetylation preceded Brg1 binding in a MyoD-dependent manner but that MyoD binding occurred subsequent to H4 modification and Brg1 interaction. In the absence of functional SWI/SNF enzymes, muscle regulatory proteins did not bind to the myogenin promoter, thereby providing …

The Effect Of Rooibos Tea (Aspalathus Linearis) On The Survival And Transformation Of C3h-Bt1 Mouse Fibroblasts, Krista M. Beach, Paul J. Smith

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.

The Antitumor Agent, Arglabin-Dma, Preferentially Induces Apoptosis In Human Colon Tumor Cells, Sung Wook Kwon

Theses and Dissertations in Biomedical Sciences

Arglabin-DMA, an analog of farnesyl pyrophosphate (FPP), reportedly inhibits farnesyltransferase (FTase) directly by competitively blocking the binding of Ras protein and its posttranslational modification, as suggested in previous studies. But, the mechanisms by which Arglabin-DMA inhibits tumor growth in vivo and in vitro are still relatively poorly characterized. To determine the mechanism by which this drug inhibits tumor growth, the effects of Arglabin-DMA in two human colon tumor cell lines (mutant K-ras HCT 116 and wild-type ras HT-29) were explored on cell proliferation, apoptosis, and cell cycle kinetics in vitro. In cell viability studies, we showed that Arglabin-DMA …

Developing And Optimizing Conditions For Single Cell Genetic Analysis, Susan Adele Gitlin

Theses and Dissertations in Biomedical Sciences

Preimplantation Genetic Diagnosis (PGD) allows for couples to obtain genetic information at the embryo stage, therefore preventing lethal genetic diseases in their offspring. A recent multi-center study determined a 17% amplification failure rate overall and a 3.4% misdiagnosis rate (ESHRE PGD consortium steering committee, 2002). Experiments presented here were conducted to decrease those rates by optimizing single cell sensitivity and specificity of PGD techniques. Primer extension preamplification (PEP) was used after initial amplification failure, followed by gene specific PCR. Reamplification experiments yielded 54% amplification rates using blastomeres that previously failed amplification. In the clinical trial, four of six blastomeres were …

Effect Of Ionizing Radiation On Trichomonas Vaginalis: Increase In Red Pigmented Intracellular Bodies Associated With Irradiated Cells, James J. Daly Sr., Terryl L. Hostetler, Max L. Baker

Journal of the Arkansas Academy of Science

No abstract provided.

A Dynamin-3 Spliced Variant Modulates The Actin/Cortactin-Dependent Morphogenesis Of Dendritic Spines, Noah W. Gray, Anne E. Kruchten, Jing Chen, Mark A. Mcniven

Faculty Publications

Immature dendrites extend many actin-rich filopodial structures that can be replaced by synapse-containing dendritic spines as the neuron matures. The large GTPase dynamin-3 (Dyn3) is a component of the postsynapse in hippocampal neurons but its function is undefined. Here, we demonstrate that a specific Dyn3 variant (Dyn3baa) promotes the formation of immature dendritic filopodia in cultured neurons. This effect is dependent upon Dyn3 GTPase activity and a direct interaction with the F-actin-binding protein cortactin. Consistent with these findings, Dyn3baa binds to cortactin with a 200% higher affinity than Dyn3aaa, a near identical isoform that does not induce dendritic filopodia when …

Cortactin Regulates Cell Migration Via Activation Of N-Wasp, Jennifer Kowalski, C. Egile, S. Gil, S. B. Snapper, R. Li, S. M. Thomas

Scholarship and Professional Work - LAS

Cortactin is an actin-associated scaffolding protein that regulates cell migration. Amplification of the human gene, EMS1, has been detected in breast, head and neck tumors, where it correlates with increased invasiveness. Cortactin can regulate actin dynamics directly via its N-terminal half, which can bind and activate the Arp2/3 complex. The C-terminal portion of cortactin, however, is thought to have limited function in its regulation of the actin polymerization machinery. In this report, we identify a role for the cortactin C-terminus in regulating cell migration and, more specifically, actin dynamics. Overexpression of either full-length cortactin or cortactin C-terminus is sufficient to …

Biphasic Functions Of The Kinase-Defective Ephb6 Receptor In Cell Adhesion And Migration, Hiroshi Matsuoka, Hiroya Obama, Meghan Kelly, Toshimitsu Matsui, Masaru Nakamoto

Biology Faculty Publications

EphB6 is a unique member in the Eph family of receptor tyrosine kinases in that its kinase domain contains several alterations in conserved amino acids and is catalytically inactive. Although EphB6 is expressed both in a variety of embryonic and adult tissues, biological functions of this receptor are largely unknown. In the present study, we examined the function of EphB6 in cell adhesion and migration. We demonstrated that EphB6 exerted biphasic effects in response to different concentrations of the ephrin-B2 ligand; EphB6 promoted cell adhesion and migration when stimulated with low concentrations of ephrin-B2, whereas it induced repulsion and inhibited …

Synthesis And Evaluation Of New Cathepsin D Inhibitors, Rose M. Mcconnell, Walter E. Godwin, Kelley Sayyer, Carol Trana, Adam Green, Matthew Mcconnell, Ashley Young, Lauren Young, Susan E. Hatfield

Journal of the Arkansas Academy of Science

Cathepsin D, a lysosomal aspartic protease, has been suggested to play a role in the metastatic potential of several types of cancer A high activated cathepsin D level in breast tumor tissue has been associated with an increased incidence of relapse and metastasis. High levels of active cathepsin D have also been found in colon cancer, prostate cancer, uterine cancer, and ovarian cancer. Hydroxyethyl isosteres with cyclic tertiary amine have proven to be clinically useful as inhibitors of aspartyl proteases, such as cathepsin D and the HIV1 aspartyl protease. Also cathepsin D has recently been associated with the development of …

Selective Field Effects On Intracellular Vacuoles And Vesicle Membranes With Nanosecond Electric Pulses, Ephrem Tekle, Hammou Oubrahim, Sergey M. Dzekunov, Juergen F. Kolb, Karl H. Schoenbach

Bioelectrics Publications

Electric pulses across intact vesicles and cells can lead to transient increase in permeability of their membranes. We studied the integrity of these membranes in response to external electric pulses of high amplitude and submicrosecond duration with a primary aim of achieving selective permeabilization. These effects were examined in two separate model systems comprising of 1), a mixed population of 1,2-di-oleoyl-sn-glycero-3-phosphocholine phospholipid vesicles and in 2), single COS-7 cells, in which large endosomal membrane vacuoles were induced by stimulated endocytosis. It has been shown that large and rapidly varying external electric fields, with pulses shorter than the charging time of …

Regulation Of Sparc Gene Expression By The Activator Protein 1 Transcription Factor, Joseph William Briggs

Theses and Dissertations in Biomedical Sciences

Overexpression of the c-Jun proto-oncogene in MCF7 breast cancer cells results in a variety of phenotypic changes related to malignant progression including a shift to estrogen independent growth, increased cell motility and invasion. Concurrent with these phenotypic changes are alterations to cellular gene expression patterns. One gene that becomes highly upregulated is SPARC (secreted protein acidic and rich in cysteine). Increased SPARC expression is associated with malignant progression in a variety of different cancers, although little is known regarding the mechanisms of SPARC gene regulation. Therefore, the objectives of this study were: (1) to determine the mechanisms by which c-Jun …

Characterization Of Migrating Cells From Ventricular Zone (Vz) To Distant Limbic Structures After Multiple Neonatal Seizures, Melissa Corcia

Seton Hall University Dissertations and Theses (ETDs)

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Biomarkers For Placental Abnormality, Cathal Mccarthy

Doctoral

Obstetrical complications including recurrent miscarriage, pre-eclampsia and intrauterine growth restriction (IUGR) affect 1%-5% of pregnant women (Younis and Samueloff 2003). Dysfunctional trophoblasts, impaired development of spiral arteries, imbalance in systems controlling the dilation and contraction of spiral arteries, placental fibrin clots and intervillous thrombosis are all possible factors that can result in an insufficient placental circulation. The combination of the hypercoagulable state of pregnancy and presence of genetic thrombophilic markets has the potential to induce placental thrombosis and cause placental insufficiency with subsequent obstetrical complications. The initial part of the research work involved examining the relationship between four common genetic …

Natural History And Karyology Of The Yucatán Vesper Mouse, Otonyctomys Hatti, Hugh H. Genoways, Robert M. Timm, Mark D. Engstrom

University of Nebraska State Museum: Mammalogy Papers

Seventeen specimens of the rare Yucatán vesper mouse, Otonyctomys hatti, are now known from Belize, Guatemala, and the Mexican states of Campeche, Quintana Roo, and Yucatán. We herein report a second specimen of O. hatti, from Belize, extending the known geographic range of the species 95 km to the southeast in the country. This is the first location at which O. hatti has been taken sympatrically with the Central American vesper mouse, Nyctomys sumichrasti. We also report data on three additional specimens of O. hatti from Campeche. Nyctomys and Otonyctomys share similar habits and habitat requirements, and …

On The Enigmatic Distribution Of The Honduran Endemic Leptodactylus Silvanimbus (Amphibia: Anura: Lep Todactylidae), W. Ronald Heyer, Rafael O. De Sá, Sarah Muller

Biology Faculty Publications

Most species of the frog genus Leptodactylus occur in South America, and all authors who have treated the zoogeography of the genus have concluded that it originated somewhere in South America (e.g., Savage 1982). Savage (1982,518) summarized the historical herpetofaunal units of the Neotropics as follows: "All evidence points to an ancient contiguity and essential similarity of a generalized tropical herpetofauna that ranged over tropical North, Middle, and most of South America in Cretaceous-Paleocene times. Descendents of this fauna are represented today by the South and Middle American tracks (Elements). To the north of this fauna ranged a subtropical-temperate Laurasian …