Life Sciences Commons^™

Floxed-Cassette Allelic Exchange Mutagenesis Enables Markerless Gene Deletion In Chlamydia Trachomatis And Can Reverse Cassette-Induced Polar Effects, Gabrielle Keb, Robert Hayman, Kenneth A. Fields

Microbiology, Immunology, and Molecular Genetics Faculty Publications

As obligate intracellular bacteria, Chlamydia spp. have evolved numerous, likely intricate, mechanisms to create and maintain a privileged intracellular niche. Recent progress in elucidating and characterizing these processes has been bolstered by the development of techniques enabling basic genetic tractability. Florescence-reported allelic exchange mutagenesis (FRAEM) couples chromosomal gene deletion with the insertion of a selection cassette encoding antibiotic resistance and green fluorescent protein (GFP). Similar to other bacteria, many chlamydial genes exist within polycistronic operons, raising the possibility of polar effects mediated by insertion cassettes. Indeed, FRAEM-mediated deletion of Chlamydia trachomatis tmeA negatively impacts the expression of tmeB. We …

Dna Methylation By Restriction Modification Systems Affects The Global Transcriptome Profile In Borrelia Burgdorferi, Timothey Casselli, Yvonne Tourand, Adam Scheidegger, William K. Arnold, Anna Proulx, Brian Stevenson, Catherine A. Brissette

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Prokaryote restriction modification (RM) systems serve to protect bacteria from potentially detrimental foreign DNA. Recent evidence suggests that DNA methylation by the methyltransferase (MTase) components of RM systems can also have effects on transcriptome profiles. The type strain of the causative agent of Lyme disease, Borrelia burgdorferi B31, possesses two RM systems with N6-methyladenosine (m6A) MTase activity, which are encoded by the bbe02 gene located on linear plasmid lp25 and bbq67 on lp56. The specific recognition and/or methylation sequences had not been identified for either of these B. burgdorferi MTases, and it was not previously known whether these RM …

Antibody Epitope Specificity For Dsdna Phosphate Backbone Is An Intrinsic Property Of The Heavy Chain Variable Germline Gene Segment Used, Tatjana Srdic-Rajic, Heinz Kohler, Vladimir Jurisic, Radmila Metlas

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Analysis of protein sequences by the informational spectrum method (ISM) enables characterization of their specificity according to encoded information represented with defined frequency (F). Our previous data showed that F(0.367) is characteristic for variable heavy chain (VH) domains (a combination of variable (V), diversity (D) and joining (J) gene segments) of the anti-phosphocholine (PC) T15 antibodies and mostly dependent on the CDR2 region, a site for PC phosphate group binding. Because the T15 dsDNA-reactive U4 mutant also encodes F(0.367), we hypothesized that the same frequency may also be characteristic for anti-DNA antibodies. Data obtained from an analysis of 60 spontaneously …

Transcriptomic Insights On The Virulence-Controlling Csra, Badr, Rpon, And Rpos Regulatory Networks In The Lyme Disease Spirochete, William K. Arnold, Christina R. Savage, Kathryn G. Lethbridge, Trever C. Smith, Catherine A. Brisette, Janakiram Seshu, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Borrelia burgdorferi, the causative agent of Lyme disease, survives in nature through a cycle that alternates between ticks and vertebrates. To facilitate this defined lifestyle, B. burgdorferi has evolved a gene regulatory network that ensures transmission between those hosts, along with specific adaptations to niches within each host. Several regulatory proteins are known to be essential for the bacterium to complete these critical tasks, but interactions between regulators had not previously been investigated in detail, due to experimental uses of different strain backgrounds and growth conditions. To address that deficit in knowledge, the transcriptomic impacts of four critical …

Novel Role Of Prostate Apoptosis Response-4 Tumor Suppressor In B-Cell Chronic Lymphocytic Leukemia, Mary Kathryn Mckenna, Sunil K. Noothi, Sara S. Alhakeem, Karine Z. Oben, Joseph T. Greene, Rajeswaran Mani, Kathryn L. Perry, James P. Collard, Jacqueline R. Rivas, Gerhard C. Hildebrandt, Roger A. Fleischman, Eric B. Durbin, John C. Byrd, Chi Wang, Natarajan Muthusamy, Vivek M. Rangnekar, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Prostate apoptosis response-4 (Par-4), a proapoptotic tumor suppressor protein, is downregulated in many cancers including renal cell carcinoma, glioblastoma, endometrial, and breast cancer. Par-4 induces apoptosis selectively in various types of cancer cells but not normal cells. We found that chronic lymphocytic leukemia (CLL) cells from human patients and from Eµ-Tcl1 mice constitutively express Par-4 in greater amounts than normal B-1 or B-2 cells. Interestingly, knockdown of Par-4 in human CLL-derived Mec-1 cells results in a robust increase in p21/WAF1 expression and decreased growth due to delayed G1-to-S cell-cycle transition. Lack of Par-4 also increased the expression of p21 and …

Borrelia Burgdorferi Spovg Dna- And Rna-Binding Protein Modulates The Physiology Of The Lyme Disease Spirochete, Christina R. Savage, Brandon L. Jutras, Aaron Bestor, Kit Tilly, Patricia A. Rosa, Yvonne Tourand, Philip E. Stewart, Catherine A. Brissette, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The SpoVG protein of Borrelia burgdorferi, the Lyme disease spirochete, binds to specific sites of DNA and RNA. The bacterium regulates transcription of spoVG during the natural tick-mammal infectious cycle and in response to some changes in culture conditions. Bacterial levels of spoVG mRNA and SpoVG protein did not necessarily correlate, suggesting that posttranscriptional mechanisms also control protein levels. Consistent with this, SpoVG binds to its own mRNA, adjacent to the ribosome-binding site. SpoVG also binds to two DNA sites in the glpFKD operon and to two RNA sites in glpFKD mRNA; that operon encodes genes necessary for glycerol catabolism …

Microbial Co-Infection Alters Macrophage Polarization, Phagosomal Escape, And Microbial Killing, Nikita H. Trivedi, Jieh-Juen Yu, Chiung-Yu Hung, Richard P. Doelger, Christopher S. Navara, Lisa Y. Armitige, Janakiram Seshu, Anthony P. Sinai, James P. Chambers, M. Neal Guentzel, Bernard P. Arulanandam

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Macrophages are important innate immune cells that respond to microbial insults. In response to multi-bacterial infection, the macrophage activation state may change upon exposure to nascent mediators, which results in different bacterial killing mechanism(s). In this study, we utilized two respiratory bacterial pathogens, Mycobacterium bovis (Bacillus Calmette Guẻrin, BCG) and Francisella tularensis live vaccine strain (LVS) with different phagocyte evasion mechanisms, as model microbes to assess the influence of initial bacterial infection on the macrophage response to secondary infection. Non-activated (M0) macrophages or activated M2-polarized cells (J774 cells transfected with the mouse IL-4 gene) were first infected with BCG for …

Neutrophils From Both Susceptible And Resistant Mice Efficiently Kill Opsonized Listeria Monocytogenes, Michelle G. Pitts, Travis A. Combs, Sarah E. F. D'Orazio

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Inbred mouse strains differ in their susceptibility to infection with the facultative intracellular bacterium Listeria monocytogenes, largely due to delayed or deficient innate immune responses. Previous antibody depletion studies suggested that neutrophils (polymorphonuclear leukocytes [PMN]) were particularly important for clearance in the liver, but the ability of PMN from susceptible and resistant mice to directly kill L. monocytogenes has not been examined. In this study, we showed that PMN infiltrated the livers of BALB/c/By/J (BALB/c) and C57BL/6 (B6) mice in similar numbers and that both cell types readily migrated toward leukotriene B4 in an in vitro chemotaxis assay. However, …

A Comparison Of Oral And Intravenous Mouse Models Of Listeriosis, Michelle G. Pitts, Sarah E. F. D'Orazio

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Listeria monocytogenes is one of several enteric microbes that is acquired orally, invades the gastric mucosa, and then disseminates to peripheral tissues to cause systemic disease in humans. Intravenous (i.v.) inoculation of mice with L. monocytogenes has been the most widely-used small animal model of listeriosis over the past few decades. The infection is highly reproducible and has been invaluable in deciphering mechanisms of adaptive immunity in vivo, particularly CD8+ T cell responses to intracellular pathogens. However, the i.v. model completely bypasses the gut phase of the infection. Recent advances in generating both humanized mice and murinized bacteria, as well …

Comparison Between Listeria Sensu Stricto And Listeria Sensu Lato Strains Identifies Novel Determinants Involved In Infection, Jakob Schardt, Grant Jones, Stefanie Müller-Herbst, Kristina Schauer, Sarah E. F. D'Orazio, Thilo M. Fuchs

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The human pathogen L. monocytogenes and the animal pathogen L. ivanovii, together with four other species isolated from symptom-free animals, form the "Listeria sensu stricto" clade. The members of the second clade, "Listeria sensu lato", are believed to be solely environmental bacteria without the ability to colonize mammalian hosts. To identify novel determinants that contribute to infection by L. monocytogenes, the causative agent of the foodborne disease listeriosis, we performed a genome comparison of the two clades and found 151 candidate genes that are conserved in the Listeria sensu stricto species. Two factors were …

Ablation Of An Ovarian Tumor Family Deubiquitinase Exposes The Underlying Regulation Governing The Plasticity Of Cell Cycle Progression In Toxoplasma Gondii, Animesh Dhara, Rodrigo De Paula Baptista, Jessica C. Kissinger, Ernest Charles Snow, Anthony P. Sinai

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Toxoplasma genome encodes the capacity for distinct architectures underlying cell cycle progression in a life cycle stage-dependent manner. Replication in intermediate hosts occurs by endodyogeny, whereas a hybrid of schizogony and endopolygeny occurs in the gut of the definitive feline host. Here, we characterize the consequence of the loss of a cell cycle-regulated ovarian tumor (OTU family) deubiquitinase, OTUD3A of Toxoplasma gondii (TgOTUD3A; TGGT1_258780), in T. gondii tachyzoites. Rather than the mutation being detrimental, mutant parasites exhibited a fitness advantage, outcompeting the wild type. This phenotype was due to roughly one-third of TgOTUD3A-knockout (TgOTUD3A-KO) tachyzoites exhibiting deviations from endodyogeny …

The Trophic Life Cycle Stage Of The Opportunistic Fungal Pathogen Pneumocystis Murina Hinders The Ability Of Dendritic Cells To Stimulate Cd4+ T Cell Responses, Heather M. Evans, Andrew Simpson, Shu Shen, Arnold J. Stromberg, Carol L. Pickett, Beth A. Garvy

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The life cycle of the opportunistic fungal pathogen Pneumocystis murina consists of a trophic stage and an ascus-like cystic stage. Infection with the cyst stage induces proinflammatory immune responses, while trophic forms suppress the cytokine response to multiple pathogen-associated molecular patterns (PAMPs), including β-glucan. A targeted gene expression assay was used to evaluate the dendritic cell response following stimulation with trophic forms alone, with a normal mixture of trophic forms and cysts, or with β-glucan. We demonstrate that stimulation with trophic forms downregulated the expression of multiple genes normally associated with the response to infection, including genes encoding …

Pro-Angiogenesis Therapy And Aging: A Mini-Review, Charles T. Ambrose

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Apart from major illnesses and chronic afflictions, the elderly experience lesser ailments, such as muscle weakness, cold intolerance, and transient memory lapses. Physical signs in the aged include wrinkled skin and the slow healing of skin abrasions. These ailments and signs are grouped together because they may be due in part to an age-linked, waning microcirculation. A reduced capillary density (CD) throughout the body of aged people and animals has been reported in over 40 papers. The reduced CD is due in turn to declining levels of angiogenic growth factors (AGFs) throughout the body during old age, as documented in …

The Feoabc Locus Of Yersinia Pestis Likely Has Two Promoters Causing Unique Iron Regulation, Lauren O'Connor, Jacqueline D. Fetherston, Robert D. Perry

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The FeoABC ferrous transporter is a wide-spread bacterial system. While the feoABC locus is regulated by a number of factors in the bacteria studied, we have previously found that regulation of feoABC in Yersinia pestis appears to be unique. None of the non-iron responsive transcriptional regulators that control expression of feoABC in other bacteria do so in Y. pestis. Another unique factor is the iron and Fur regulation of the Y. pestis feoABC locus occurs during microaerobic but not aerobic growth. Here we show that this unique iron-regulation is not due to a unique aspect of the Y. pestis …

Crystal Structure Of Yersinia Pestis Virulence Factor Yfea Reveals Two Polyspecific Metal-Binding Sites, Christopher D. Radka, Lawrence J. Delucas, Landon S. Wilson, Matthew B. Lawrenz, Robert D. Perry, Stephen G. Aller

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Gram-negative bacteria use siderophores, outer membrane receptors, inner membrane transporters and substrate-binding proteins (SBPs) to transport transition metals through the periplasm. The SBPs share a similar protein fold that has undergone significant structural evolution to communicate with a variety of differentially regulated transporters in the cell. In Yersinia pestis, the causative agent of plague, YfeA (YPO2439, y1897), an SBP, is important for full virulence during mammalian infection. To better understand the role of YfeA in infection, crystal structures were determined under several environmental conditions with respect to transition-metal levels. Energy-dispersive X-ray spectroscopy and anomalous X-ray scattering data show that …

Zinc Transporters Ybtx And Znuabc Are Required For The Virulence Of Yersinia Pestis In Bubonic And Pneumonic Plague In Mice, Alexander G. Bobrov, Olga Kirillina, Marina Y. Fosso, Jacqueline D. Fetherston, M. Clarke Miller, Tiva T. Vancleave, Joseph A. Burlison, William K. Arnold, Matthew B. Lawrenz, Sylvie Garneau-Tsodikova, Robert D. Perry

Microbiology, Immunology, and Molecular Genetics Faculty Publications

A number of bacterial pathogens require the ZnuABC Zinc (Zn²⁺) transporter and/or a second Zn²⁺ transport system to overcome Zn²⁺ sequestration by mammalian hosts. Previously we have shown that in addition to ZnuABC, Yersinia pestis possesses a second Zn²⁺ transporter that involves components of the yersiniabactin (Ybt), siderophore-dependent iron transport system. Synthesis of the Ybt siderophore and YbtX, a member of the major facilitator superfamily, are both critical components of the second Zn²⁺ transport system. Here we demonstrate that a ybtX znu double mutant is essentially avirulent in mouse models of bubonic and pneumonic …

Are Cdi Systems Multicolored, Facultative, Helping Greenbeards?, Elizabeth S. Danka, Erin C. Garcia, Peggy A. Cotter

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Competitive and cooperative interactions between organisms, including bacteria, can significantly impact the composition of a community and the fitness of its members, as well as the fitness of their hosts when communities are living on or within other organisms. Understanding the underlying mechanisms is critical to the development of strategies to control microbiological communities that impact animal and plant health and also for understanding the evolution of social behaviors, which has been challenging for evolutionary biologists. Contact-dependent growth inhibition (CDI) is a phenomenon defined by the delivery of a protein toxin to the cytoplasm of neighboring bacteria upon cell–cell contact, …

Overcoming Hurdles To Development Of A Vaccine Against Pneumocystis Jirovecii, Beth A. Garvy

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Development of Pneumocystis pneumonia (PCP) is a common problem among immunosuppressed individuals. There are windows of opportunity in which vaccination would be beneficial, but to date, no vaccines have made it to clinical trials. Significant hurdles to vaccine development include host range specificity, making it difficult to translate from animal models to humans. Discovery of cross-reactive epitopes is critical to moving vaccine candidates from preclinical animal studies to clinical trials.

Pneumocystis Infection Alters The Activation State Of Pulmonary Macrophages, Jessica M. Deckman, Cathryn J. Kurkjian, Joseph P. Mcgillis, Theodore J. Cory, Susan E. Birket, Linda M. Schutzman, Brian S. Murphy, Beth A. Garvy, David J. Feola

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Recent studies show a substantial incidence of Pneumocystis jirovecii colonization and infection in patients with chronic inflammatory lung conditions. However, little is known about the impact of Pneumocystis upon the regulation of pulmonary immunity. We demonstrate here that Pneumocystis polarizes macrophages towards an alternatively activated macrophage-like phenotype. Genetically engineered mice that lack the ability to signal through IL-4 and IL-13 were used to show that Pneumocystis alternative macrophage activation is dependent upon signaling through these cytokines. To determine whether Pneumocystis-induced macrophage polarization would impact subsequent immune responses, we infected mice with Pneumocystis and then challenged them with Pseudomonas aeruginosa 14 …

Radiation Induced Apoptosis Of Murine Bone Marrow Cells Is Independent Of Early Growth Response 1 (Egr1), Karine Z. Oben, Beth W. Gachuki, Sara S. Alhakeem, Mary Kathryn Mckenna, Ying Liang, Daret K. St. Clair, Vivek M. Rangnekar, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

An understanding of how each individual 5q chromosome critical deleted region (CDR) gene contributes to malignant transformation would foster the development of much needed targeted therapies for the treatment of therapy related myeloid neoplasms (t-MNs). Early Growth Response 1 (EGR1) is a key transcriptional regulator of myeloid differentiation located within the 5q chromosome CDR that has been shown to regulate HSC (hematopoietic stem cell) quiescence as well as the master regulator of apoptosis—p53. Since resistance to apoptosis is a hallmark of malignant transformation, we investigated the role of EGR1 in apoptosis of bone marrow cells; a cell population from which …

Reexamining Chronic Toxoplasma Gondii Infection: Surprising Activity For A "Dormant" Parasite, Anthony P. Sinai, Elizabeth A. Watts, Animesh Dhara, Robert D. Murphy, Matthew S. Gentry, Abhijit R. Patwardhan

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Purpose of Review

Despite over a third of the world’s population being chronically infected with Toxoplasma gondii, little is known about this largely asymptomatic phase of infection. This stage is mediated in vivo by bradyzoites within tissue cysts. The absence of overt symptoms has been attributed to the dormancy of bradyzoites. In this review, we reexamine the conventional view of chronic toxoplasmosis in light of emerging evidence challenging both the nature of dormancy and the consequences of infection in the CNS.

Recent Findings

New and emerging data reveal a previously unrecognized level of physiological and replicative capacity of bradyzoites …

The Life Cycle Stages Of Pneumocystis Murina Have Opposing Effects On The Immune Response To This Opportunistic Fungal Pathogen, Heather M. Evans, Grady L. Bryant Iii, Beth A. Garvy

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The cell wall β-glucans of Pneumocystis cysts have been shown to stimulate immune responses in lung epithelial cells, dendritic cells, and alveolar macrophages. Little is known about how the trophic life forms, which do not have a fungal cell wall, interact with these innate immune cells. Here we report differences in the responses of both neonatal and adult mice to the trophic and cystic life cycle stages of Pneumocystis murina. The adult and neonatal immune responses to infection with Pneumocystis murina trophic forms were less robust than the responses to infection with a physiologically normal mixture of cysts and …

Rna-Seq Of Borrelia Burgdorferi In Multiple Phases Of Growth Reveals Insights Into The Dynamics Of Gene Expression, Transcriptome Architecture, And Noncoding Rnas, William K. Arnold, Christina R. Savage, Catherine A. Brissette, Janakiram Seshu, Jonathan Livny, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Borrelia burgdorferi, the agent of Lyme disease, differentially expresses numerous genes and proteins as it cycles between mammalian hosts and tick vectors. Insights on regulatory mechanisms have been provided by earlier studies that examined B. burgdorferi gene expression patterns during cultivation. However, prior studies examined bacteria at only a single time point of cultivation, providing only a snapshot of what is likely a dynamic transcriptional program driving B. burgdorferi adaptations to changes during culture growth phases. To address that concern, we performed RNA sequencing (RNA-Seq) analysis of B. burgdorferi cultures at early-exponential, mid-exponential, and early-stationary phases …

A Cell Cycle-Regulated Toxoplasma Deubiquitinase, Tgotud3a, Targets Polyubiquitins With Specific Lysine Linkages, Animesh Dhara, Anthony P. Sinai

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The contribution of ubiquitin-mediated mechanisms in the regulation of the Toxoplasma gondii cell cycle has remained largely unexplored. Here, we describe the functional characterization of a T. gondii deubiquitinase (TGGT1_258780) of the ovarian-tumor domain-containing (OTU) family, which, based on its structural homology to the human OTUD3 clade, has been designated TgOTUD3A. The TgOTUD3A protein is expressed in a cell cycle-dependent manner mimicking its mRNA expression, indicating that it is regulated primarily at the transcriptional level. TgOTUD3A, which was found in the cytoplasm at low levels in G₁ parasites, increased in abundance with the progression of the …

Diffuse Traumatic Brain Injury Induces Prolonged Immune Sysregulation And Potentiates Hyperalgesia Following A Peripheral Immune Challenge, Rachel K. Rowe, Gavin I. Ellis, Jordan L. Harrison, Adam D. Bachstetter, Gregory F. Corder, Linda J. Van Eldik, Bradley K. Taylor, Francesc Marti, Jonathan Lifshitz

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Background: Nociceptive and neuropathic pain occurs as part of the disease process after traumatic brain injury (TBI) in humans. Central and peripheral inflammation, a major secondary injury process initiated by the traumatic brain injury event, has been implicated in the potentiation of peripheral nociceptive pain. We hypothesized that the inflammatory response to diffuse traumatic brain injury potentiates persistent pain through prolonged immune dysregulation.

Results: To test this, adult, male C57BL/6 mice were subjected to midline fluid percussion brain injury or to sham procedure. One cohort of mice was analyzed for inflammation-related cytokine levels in cortical biopsies and serum along an …

The Homophilic Domain – An Immunological Archetype, Heinz Kohler, Jagadeesh Bayry, Srinivas V. Kaveri

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The homophilic potential emerges as an important biological principle to boost the potency of immunoglobulins. Since homophilic antibodies in human and mouse sera exist prior environmental exposure, they are part of the natural antibody repertoire. Nevertheless, hemophilic properties are also identified in induced antibody repertoire. The use of homophilicity of antibodies in the adaptive immunity signifies an archetypic antibody structure. The unique feature of homophilicity in the antibody repertoire also highlights an important mechanism to boost the antibody potency to protect against infection and atherosclerosis as well to treat cancer patients.

The Significance Of A Common Idiotype (1f7) On Antibodies Against Human Immune Deficiency Virus Type 1 And Hepatitis C Virus, Sybille Muller, Matthew S. Parsons, Heinz Kohler, Michael Grant

Microbiology, Immunology, and Molecular Genetics Faculty Publications

In this review, we trace the concept and potential functional role of regulatory idiotypes in the immune response to human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency virus, and hepatitis C virus (HCV). A major idiotype involved in these viral infections is recognized and defined by a murine monoclonal antibody (1F7). Antibodies expressing the idiotype defined by 1F7 are dominant in HIV-1 infection and are also found on many broadly neutralizing antibodies against HIV-1. This regulatory idiotypic axis offers opportunities for exploitation in vaccine development for HIV-1, HCV, and other chronic viral infections.

Gene Deletion By Fluorescence-Reported Allelic Exchange Mutagenesis In Chlamydia Trachomatis, Konrad E. Mueller, Katerina Wolf, Kenneth A. Fields

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Although progress in Chlamydia genetics has been rapid, genomic modification has previously been limited to point mutations and group II intron insertions which truncate protein products. The bacterium has thus far been intractable to gene deletion or more-complex genomic integrations such as allelic exchange. Herein, we present a novel suicide vector dependent on inducible expression of a chlamydial gene that renders Chlamydia trachomatis fully genetically tractable and permits rapid reverse genetics by fluorescence-reported allelic exchange mutagenesis (FRAEM). We describe the first available system of targeting chlamydial genes for deletion or allelic exchange as well as curing plasmids from C. trachomatis …

Coordination Of Rna Polymerase Ii Pausing And 3' End Processing Factor Recruitment With Alternative Polyadenylation, Becky Fusby, Soojin Kim, Benjamin Erickson, Hyunmin Kim, Martha L. Peterson, David L Bentley

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Most mammalian genes produce transcripts whose 3' ends are processed at multiple alternative positions by cleavage/polyadenylation (CPA). Poly(A) site cleavage frequently occurs cotranscriptionally and is facilitated by CPA factor binding to the RNA polymerase II (Pol II) C-terminal domain (CTD) phosphorylated on Ser2 residues of its heptad repeats (YS₂PTSPS). The function of cotranscriptional events in the selection of alternative poly(A) sites is poorly understood. We investigated Pol II pausing, CTD Ser2 phosphorylation, and processing factor CstF recruitment at wild-type and mutant IgM transgenes that use alternative poly(A) sites to produce mRNAs encoding the secreted and membrane-bound forms of …

The Role Of Capillaries In The Lesser Ailments Of Old Age And In Alzheimer's Disease And Vascular Dementia: The Potential Of Pro-Therapeutic Angiogenesis, Charles T. Ambrose

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Apart from chronic diseases (arthritis, diabetes, etc.), old age is generally characterized by three lesser ailments: muscle weakness, minor memory lapses, and cold intolerance. This trio of complaints may have a common, underlying cause, namely, the age-associated reduced microcirculation in muscles, brain, skin, and elsewhere in the body. The Angiogenesis Hypothesis proposes that old age is in part a deficiency disease due to the decline in angiogenic (AG) factors, resulting in a reduced capillary density (CD) throughout the body. Over fifty published papers document waning levels of AG factors and/or decreased CD in various organ systems of aged animals and …