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Articles 1 - 13 of 13
Full-Text Articles in Medicine and Health Sciences
The Caenorhabditis Elegans Heterochronic Regulator Lin-14 Is A Novel Transcription Factor That Controls The Developmental Timing Of Transcription From The Insulin/Insulin-Like Growth Factor Gene Ins-33 By Direct Dna Binding, Marta Hristova, Darcy Birse, Yang Hong, Victor Ambros
The Caenorhabditis Elegans Heterochronic Regulator Lin-14 Is A Novel Transcription Factor That Controls The Developmental Timing Of Transcription From The Insulin/Insulin-Like Growth Factor Gene Ins-33 By Direct Dna Binding, Marta Hristova, Darcy Birse, Yang Hong, Victor Ambros
Dartmouth Scholarship
A temporal gradient of the novel nuclear protein LIN-14 specifies the timing and sequence of stage-specific developmental events in Caenorhabditis elegans. The profound effects of lin-14 mutations on worm development suggest that LIN-14 directly or indirectly regulates stage-specific gene expression. We show that LIN-14 can associate with chromatin in vivo and has in vitro DNA binding activity. A bacterially expressed C-terminal domain of LIN-14 was used to select DNA sequences that contain a putative consensus binding site from a pool of randomized double-stranded oligonucleotides. To identify candidates for genes directly regulated by lin-14, we employed DNA microarray hybridization to compare …
Growth Factor–Induced Shedding Of Syndecan-1 Confers Glypican-1 Dependence On Mitogenic Responses Of Cancer Cells, Kan Ding, Martha Lopez-Burks, José A. Sánchez-Duran, Murray Korc, Arthur D. Lander
Growth Factor–Induced Shedding Of Syndecan-1 Confers Glypican-1 Dependence On Mitogenic Responses Of Cancer Cells, Kan Ding, Martha Lopez-Burks, José A. Sánchez-Duran, Murray Korc, Arthur D. Lander
Dartmouth Scholarship
The cell surface heparan sulfate proteoglycan (HSPG) glypican-1 is up-regulated by pancreatic and breast cancer cells, and its removal renders such cells insensitive to many growth factors. We sought to explain why the cell surface HSPG syndecan-1, which is also up-regulated by these cells and is a known growth factor coreceptor, does not compensate for glypican-1 loss. We show that the initial responses of these cells to the growth factor FGF2 are not glypican dependent, but they become so over time as FGF2 induces shedding of syndecan-1. Manipulations that retain syndecan-1 on the cell surface make long-term FGF2 responses glypican …
A Drosophila Deg/Enac Channel Subunit Is Required For Male Response To Female Pheromones, Heping Lin, Kevin J. Mann, Elena Starostina, Ronald D. Kinser, Claudio W. Pikielny
A Drosophila Deg/Enac Channel Subunit Is Required For Male Response To Female Pheromones, Heping Lin, Kevin J. Mann, Elena Starostina, Ronald D. Kinser, Claudio W. Pikielny
Dartmouth Scholarship
Odorants and pheromones as well as sweet- and bitter-tasting small molecules are perceived through activation of G protein-coupled chemosensory receptors. In contrast, gustatory detection of salty and sour tastes may involve direct gating of sodium channels of the DEG/ENaC family by sodium and hydrogen ions, respectively. We have found that ppk25, a Drosophila melanogaster gene encoding a DEG/ENaC channel subunit, is expressed at highest levels in the male appendages responsible for gustatory and olfactory detection of female pheromones: the legs, wings, and antennae. Mutations in the ppk25 gene reduce or even abolish male courtship response to females in the dark, …
Tcpf Is A Soluble Colonization Factor And Protective Antigen Secreted By El Tor And Classical O1 And O139 Vibrio Cholerae Serogroups, Thomas J. Kirn, Ronald K. Taylor
Tcpf Is A Soluble Colonization Factor And Protective Antigen Secreted By El Tor And Classical O1 And O139 Vibrio Cholerae Serogroups, Thomas J. Kirn, Ronald K. Taylor
Dartmouth Scholarship
Vibrio cholerae causes diarrhea by colonizing the human small bowel and intoxicating epithelial cells. Colonization is a required step in pathogenesis, and strains defective for colonization are significantly attenuated. The best-characterized V. cholerae colonization factor is the toxin-coregulated pilus (TCP). It has been demonstrated that TCP is required for V. cholerae colonization in both humans and mice. TCP enhances bacterial interactions that allow microcolony formation and thereby promotes survival in the intestine. We have recently discovered that the TCP biogenesis apparatus also serves as a secretion system, mediating the terminal step in the extracellular secretion pathway of TcpF. TcpF was …
Sara Positively Controls Bap-Dependent Biofilm Formation In Staphylococcus Aureus, María P. Trotonda, Adhar C. Manna, Ambrose L. Cheung, Iñigo Lasa, José R. Penadés
Sara Positively Controls Bap-Dependent Biofilm Formation In Staphylococcus Aureus, María P. Trotonda, Adhar C. Manna, Ambrose L. Cheung, Iñigo Lasa, José R. Penadés
Dartmouth Scholarship
The biofilm-associated protein Bap is a staphylococcal surface protein involved in biofilm formation. We investigated the influence of the global regulatory locus sarA on bap expression and Bap-dependent biofilm formation in three unrelated Staphylococcus aureus strains. The results showed that Bap-dependent biofilm formation was diminished in the sarA mutants by an agr-independent mechanism. Complementation studies using a sarA clone confirmed that the defect in biofilm formation was due to the sarA mutation. As expected, the diminished capacity to form biofilms in the sarA mutants correlated with the decreased presence of Bap in the bacterial surface. Using transcriptional fusion and …
Effects Of Estradiol On Lipopolysaccharide And Pam3cys Stimulation Of Ccl20/Macrophage Inflammatory Protein 3 Alpha And Tumor Necrosis Factor Alpha Production By Uterine Epithelial Cells In Culture, Mardi A. Crane-Godreau, Charles R. Wira
Effects Of Estradiol On Lipopolysaccharide And Pam3cys Stimulation Of Ccl20/Macrophage Inflammatory Protein 3 Alpha And Tumor Necrosis Factor Alpha Production By Uterine Epithelial Cells In Culture, Mardi A. Crane-Godreau, Charles R. Wira
Dartmouth Scholarship
We have previously demonstrated that rat uterine epithelial cells (UEC) produce CCL20/macrophage inflammatory protein 3 alpha (MIP3alpha) and tumor necrosis factor alpha (TNF-alpha) in response to live and heat-killed Escherichia coli and to the pathogen-associated molecular patterns (PAMP) lipopolysaccharide (LPS) and Pam3Cys. To determine whether estradiol (E2) modulates PAMP-induced CCL20/MIP3alpha and TNF-alpha secretion, primary cultures of rat UEC were incubated with E2 for 24 h and then treated with LPS or Pam3Cys or not treated for an additional 12 h. E2 inhibited the constitutive secretion of TNF-alpha and CCL20/MIP3alpha into culture media. Interestingly, E2 pretreatment enhanced CCL20/MIP3alpha secretion due to …
Erythroid Cell-Specific Α-Globin Gene Regulation By The Cp2 Transcription Factor Family, Ho C. Kang, Jui Hyung Chae, Yeon H. Lee, Mi-Ae Park, June Ho Shin, Sung-Hyun Kim, Sang-Kyu Ye, Yoon Shin Cho, Steven Fiering, Chul Geun Kim
Erythroid Cell-Specific Α-Globin Gene Regulation By The Cp2 Transcription Factor Family, Ho C. Kang, Jui Hyung Chae, Yeon H. Lee, Mi-Ae Park, June Ho Shin, Sung-Hyun Kim, Sang-Kyu Ye, Yoon Shin Cho, Steven Fiering, Chul Geun Kim
Dartmouth Scholarship
We previously demonstrated that ubiquitously expressed CP2c exerts potent erythroid-specific transactivation of alpha-globin through an unknown mechanism. This mechanism is reported here to involve specific CP2 splice variants and protein inhibitor of activated STAT1 (PIAS1). We identify a novel murine splice isoform of CP2, CP2b, which is identical to CP2a except that it has an additional 36 amino acids encoded by an extra exon. CP2b has an erythroid cell-specific transcriptional activation domain, which requires the extra exon and can form heteromeric complexes with other CP2 isoforms, but lacks the DNA binding activity found in CP2a and CP2c. Transcriptional activation of …
A Human T-Cell Lymphotropic Virus Type 1 Enhancer Of Myc Transforming Potential Stabilizes Myc-Tip60 Transcriptional Interactions, Soumya Awasthi, Anima Sharma, Kasuen Wong, Junyu Zhang, Elizabeth F. Matlock, Lowery Rogers, Pamela Motloch, Shigeki Takemoto, Hirokuni Taguchi, Michael D. Cole
A Human T-Cell Lymphotropic Virus Type 1 Enhancer Of Myc Transforming Potential Stabilizes Myc-Tip60 Transcriptional Interactions, Soumya Awasthi, Anima Sharma, Kasuen Wong, Junyu Zhang, Elizabeth F. Matlock, Lowery Rogers, Pamela Motloch, Shigeki Takemoto, Hirokuni Taguchi, Michael D. Cole
Dartmouth Scholarship
The human T-cell lymphotropic virus type 1 (HTLV-1) infects and transforms CD4+ lymphocytes and causes adult T-cell leukemia/lymphoma (ATLL), an aggressive lymphoproliferative disease that is often fatal. Here, we demonstrate that the HTLV-1 pX splice-variant p30II markedly enhances the transforming potential of Myc and transcriptionally activates the human cyclin D2 promoter, dependent upon its conserved Myc-responsive E-box enhancer elements, which are associated with increased S-phase entry and multinucleation. Enhancement of c-Myc transforming activity by HTLV-1 p30II is dependent upon the transcriptional coactivators, transforming transcriptional activator protein/p434 and TIP60, and it requires TIP60 histone acetyltransferase (HAT) activity and correlates with the …
The Cns Role Of Toll-Like Receptor 4 In Innate Neuroimmunity And Painful Neuropathy, Flobert Y. Tanga, Nancy Nutile-Mcmenemy, Joyce A. Deleo
The Cns Role Of Toll-Like Receptor 4 In Innate Neuroimmunity And Painful Neuropathy, Flobert Y. Tanga, Nancy Nutile-Mcmenemy, Joyce A. Deleo
Dartmouth Scholarship
Neuropathic pain remains a prevalent and persistent clinical problem because of our incomplete understanding of its pathogenesis. This study demonstrates for the first time, to our knowledge, a critical role for CNS innate immunity by means of microglial Toll-like receptor 4 (TLR4) in the induction phase of behavioral hypersensitivity in a mouse and rat model of neuropathy. We hypothesized that after L5 nerve transection, CNS neuroimmune activation and subsequent cytokine expression are triggered by the stimulation of microglial membrane-bound TLR4. To test this hypothesis, experiments were undertaken to assess tactile and thermal hypersensitivity in genetically altered (i.e., TLR4 knockout and …
Role For Akt3/Protein Kinase Bγ In Attainment Of Normal Brain Size, Rachel M. Easton, Han Cho, Kristin Roovers, Diana W. Shineman
Role For Akt3/Protein Kinase Bγ In Attainment Of Normal Brain Size, Rachel M. Easton, Han Cho, Kristin Roovers, Diana W. Shineman
Dartmouth Scholarship
Studies of Drosophila and mammals have revealed the importance of insulin signaling through phosphatidylinositol 3-kinase and the serine/threonine kinase Akt/protein kinase B for the regulation of cell, organ, and organismal growth. In mammals, three highly conserved proteins, Akt1, Akt2, and Akt3, comprise the Akt family, of which the first two are required for normal growth and metabolism, respectively. Here we address the function of Akt3. Like Akt1, Akt3 is not required for the maintenance of normal carbohydrate metabolism but is essential for the attainment of normal organ size. However, in contrast to Akt1−/− mice, which display a …
Dynamic Changes In Mcl-1 Expression Regulate Macrophage Viability Or Commitment To Apoptosis During Bacterial Clearance, Helen M. Marriott, Colin D. Bingle, Robert C. Read, Karen E. Braley, Guido Kroemer, Paul G. Hellewell, Ruth W. Craig, Moira K.B. Whyte, David H. Dockrell
Dynamic Changes In Mcl-1 Expression Regulate Macrophage Viability Or Commitment To Apoptosis During Bacterial Clearance, Helen M. Marriott, Colin D. Bingle, Robert C. Read, Karen E. Braley, Guido Kroemer, Paul G. Hellewell, Ruth W. Craig, Moira K.B. Whyte, David H. Dockrell
Dartmouth Scholarship
Macrophages are critical effectors of bacterial clearance and must retain viability, despite exposure to toxic bacterial products, until key antimicrobial functions are performed. Subsequently, host-mediated macrophage apoptosis aids resolution of infection. The ability of macrophages to make this transition from resistance to susceptibility to apoptosis is important for effective host innate immune responses. We investigated the role of Mcl-1, an essential regulator of macrophage lifespan, in this switch from viability to apoptosis, using the model of pneumococcal-associated macrophage apoptosis. Upon exposure to pneumococci, macrophages initially upregulate Mcl-1 protein and maintain viability for up to 14 hours. Subsequently, macrophages reduce expression …
A Three-Component Regulatory System Regulates Biofilm Maturation And Type Iii Secretion In Pseudomonas Aeruginosa, Sherry L. Kuchma, John P. Connolly, George A. O'Toole
A Three-Component Regulatory System Regulates Biofilm Maturation And Type Iii Secretion In Pseudomonas Aeruginosa, Sherry L. Kuchma, John P. Connolly, George A. O'Toole
Dartmouth Scholarship
Biofilms are structured communities found associated with a wide range of surfaces. Here we report the identification of a three-component regulatory system required for biofilm maturation by Pseudomonas aeruginosa strain PA14. A transposon mutation that altered biofilm formation in a 96-well dish assay originally defined this locus, which is comprised of genes for a putative sensor histidine kinase and two response regulators and has been designated sadARS. Nonpolar mutations in any of the sadARS genes result in biofilms with an altered mature structure but do not confer defects in growth or early biofilm formation, swimming, or twitching motility. After …
Endothelial-Specific Expression Of Caveolin-1 Impairs Microvascular Permeability And Angiogenesis, Philip M. Bauer, Jun Yu, Yan Chen, Reed Hickey, Pascal N. Bernatchez, Robin Looft-Wilson, Yan Huang, Frank Giordano, Radu V. Stan, William C. Sessa
Endothelial-Specific Expression Of Caveolin-1 Impairs Microvascular Permeability And Angiogenesis, Philip M. Bauer, Jun Yu, Yan Chen, Reed Hickey, Pascal N. Bernatchez, Robin Looft-Wilson, Yan Huang, Frank Giordano, Radu V. Stan, William C. Sessa
Dartmouth Scholarship
The functions of caveolae and/or caveolins in intact animals are beginning to be explored. Here, by using endothelial cell-specific transgenesis of the caveolin-1 (Cav-1) gene in mice, we show the critical role of Cav-1 in several postnatal vascular paradigms. First, increasing levels of Cav-1 do not increase caveolae number in the endothelium in vivo. Second, despite a lack of quantitative changes in organelle number, endothelial-specific expression of Cav-1 impairs endothelial nitric oxide synthase activation, endothelial barrier function, and angiogenic responses to exogenous VEGF and tissue ischemia. In addition, VEGF-mediated phosphorylation of Akt and its substrate, endothelial nitric oxide synthase, were …