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Full-Text Articles in Cell and Developmental Biology

Trip/Nopo E3 Ubiquitin Ligase Promotes Ubiquitylation Of Dna Polymerase Η, Heather A. Wallace, Julie A. Merkle, Michael C. Yu, Taloa G. Berg, Ethan Lee, Giovanni Bosco, Laura A. Lee Jan 2014

Trip/Nopo E3 Ubiquitin Ligase Promotes Ubiquitylation Of Dna Polymerase Η, Heather A. Wallace, Julie A. Merkle, Michael C. Yu, Taloa G. Berg, Ethan Lee, Giovanni Bosco, Laura A. Lee

Dartmouth Scholarship

We previously identified a Drosophila maternal effect-lethal mutant named ‘no poles’ (nopo). Embryos from nopo females undergo mitotic arrest with barrel-shaped, acentrosomal spindles during the rapid cycles of syncytial embryogenesis because of activation of a Chk2-mediated DNA checkpoint. NOPO is the Drosophila homolog of human TNF receptor associated factor (TRAF)-interacting protein (TRIP), which has been implicated in TNF signaling. NOPO and TRIP contain RING domains closely resembling those of known E3 ubiquitin ligases. We herein sought to elucidate the mechanism by which TRIP/NOPO promotes genomic stability by performing a yeast two-hybrid screen to identify potential substrates/interactors. We identified members of …


Adam17-Mediated Processing Of Tnf-Α Expressed By Antiviral Effector Cd8+ T Cells Is Required For Severe T-Cell-Mediated Lung Injury, Matthew P. Deberge, Kenneth H. Ely, Guang-Shing Cheng, Richard I. Enelow Nov 2013

Adam17-Mediated Processing Of Tnf-Α Expressed By Antiviral Effector Cd8+ T Cells Is Required For Severe T-Cell-Mediated Lung Injury, Matthew P. Deberge, Kenneth H. Ely, Guang-Shing Cheng, Richard I. Enelow

Dartmouth Scholarship

Influenza infection in humans evokes a potent CD8+ T-cell response, which is important for clearance of the virus but may also exacerbate pulmonary pathology. We have previously shown in mice that CD8+ T-cell expression of TNF-a is required for severe and lethal lung injury following recognition of an influenza antigen expressed by alveolar epithelial cells. Since TNF-a is first expressed as a transmembrane protein that is then proteolytically processed to release a soluble form, we sought to characterize the role of TNF-a processing in CD8+ T-cell-mediated injury. In this study we observed that inhibition of ADAM17-mediated processing of TNF-a by …


Pv1 Down-Regulation Via Shrna Inhibits The Growth Of Pancreatic Adenocarcinoma Xenografts, Sophie J. Deharvengt, Dan Tse, Olga Sideleva, Caitlin Mcgarry, Jason R. Gunn, Daniel S. Longnecker, Catherine Carriere, Radu V. Stan May 2012

Pv1 Down-Regulation Via Shrna Inhibits The Growth Of Pancreatic Adenocarcinoma Xenografts, Sophie J. Deharvengt, Dan Tse, Olga Sideleva, Caitlin Mcgarry, Jason R. Gunn, Daniel S. Longnecker, Catherine Carriere, Radu V. Stan

Dartmouth Scholarship

PV1 is an endothelial-specific protein with structural roles in the formation of diaphragms in endothelial cells of normal vessels. PV1 is also highly expressed on endothelial cells of many solid tumours. On the basis of in vitro data, PV1 is thought to actively participate in angiogenesis. To test whether or not PV1 has a function in tumour angiogenesis and in tumour growth in vivo, we have treated pancreatic tumour-bearing mice by single-dose intratumoural delivery of lentiviruses encoding for two different shRNAs targeting murine PV1. We find that PV1 down-regulation by shRNAs inhibits the growth of established tumours derived from two …


Adenomatous Polyposis Coli Is Present Near The Minimal Level Required For Accurate Graded Responses To The Wingless Morphogen, Hassina Benchabane, Edward G. Hughes, Carter M. Takacs, Jason R. Baird, Yashi Ahmed Jan 2008

Adenomatous Polyposis Coli Is Present Near The Minimal Level Required For Accurate Graded Responses To The Wingless Morphogen, Hassina Benchabane, Edward G. Hughes, Carter M. Takacs, Jason R. Baird, Yashi Ahmed

Dartmouth Scholarship

The mechanisms by which the Wingless (Wg) morphogen modulates the activity of the transcriptional activator Armadillo (Arm) to elicit precise, concentration-dependent cellular responses remain uncertain. Arm is targeted for proteolysis by the Axin/Adenomatous polyposis coli (Apc1 and Apc2)/Zeste-white 3 destruction complex, and Wg-dependent inactivation of destruction complex activity is crucial to trigger Arm signaling. In the prevailing model for Wg transduction, only Axin levels limit destruction complex activity, whereas Apc is present in vast excess. To test this model, we reduced Apc activity to different degrees, and analyzed the effects on three concentration-dependent responses to Arm signaling that specify distinct …


Aging Predisposes Oocytes To Meiotic Nondisjunction When The Cohesin Subunit Smc1 Is Reduced, Vijayalakshmi V. Subramanian, Sharon E. Bickel Jan 2008

Aging Predisposes Oocytes To Meiotic Nondisjunction When The Cohesin Subunit Smc1 Is Reduced, Vijayalakshmi V. Subramanian, Sharon E. Bickel

Dartmouth Scholarship

In humans, meiotic chromosome segregation errors increase dramatically as women age, but the molecular defects responsible are largely unknown. Cohesion along the arms of meiotic sister chromatids provides an evolutionarily conserved mechanism to keep recombinant chromosomes associated until anaphase I. One attractive hypothesis to explain age- dependent nondisjunction (NDJ) is that loss of cohesion over time causes recombinant homologues to dissociate prematurely and segregate randomly during the first meiotic division. Using Drosophila as a model system, we have tested this hypothesis and observe a significant increase in meiosis I NDJ in experimentally aged Drosophila oocytes when the cohesin protein SMC1 …


Regulation Of Meiotic Cohesion And Chromosome Core Morphogenesis During Pachytene In Drosophila Oocytes, Radhika S. Khetani, Sharon E. Bickel Jul 2007

Regulation Of Meiotic Cohesion And Chromosome Core Morphogenesis During Pachytene In Drosophila Oocytes, Radhika S. Khetani, Sharon E. Bickel

Dartmouth Scholarship

During meiosis, cohesion between sister chromatids is required for normal levels of homologous recombination, maintenance of chiasmata and accurate chromosome segregation during both divisions. In Drosophila, null mutations in the ord gene abolish meiotic cohesion, although how ORD protein promotes cohesion has remained elusive. We show that SMC subunits of the cohesin complex colocalize with ORD at centromeres of ovarian germ-line cells. In addition, cohesin SMCs and ORD are visible along the length of meiotic chromosomes during pachytene and remain associated with chromosome cores following DNase I digestion. In flies lacking ORD activity, cohesin SMCs fail to accumulate at oocyte …


The Allantois And Chorion, When Isolated Before Circulation Or Chorio-Allantoic Fusion, Have Hematopoietic Potential, Brandon M. Zeigler, Daisuke Sugiyama, Michael Chen, Yalin Guo, K. M. Downs, N. A. Speck Nov 2006

The Allantois And Chorion, When Isolated Before Circulation Or Chorio-Allantoic Fusion, Have Hematopoietic Potential, Brandon M. Zeigler, Daisuke Sugiyama, Michael Chen, Yalin Guo, K. M. Downs, N. A. Speck

Dartmouth Scholarship

The chorio-allantoic placenta forms through the fusion of the allantois (progenitor tissue of the umbilical cord), with the chorionic plate. The murine placenta contains high levels of hematopoietic stem cells, and is therefore a stem cell niche. However, it is not known whether the placenta is a site of hematopoietic cell emergence, or whether hematopoietic cells originate from other sites in the conceptus and then colonize the placenta. Here, we show that the allantois and chorion, isolated prior to the establishment of circulation, have the potential to give rise to myeloid and definitive erythroid cells following explant culture. We further …


The Caenorhabditis Elegans F-Box Protein Sel-10 Promotes Female Development And May Target Fem-1 And Fem-3 For Degradation By The Proteasome, Sibylle Jager, Hillel T. Schwartz, H. Robert Horvitz, Barbara Conradt Aug 2004

The Caenorhabditis Elegans F-Box Protein Sel-10 Promotes Female Development And May Target Fem-1 And Fem-3 For Degradation By The Proteasome, Sibylle Jager, Hillel T. Schwartz, H. Robert Horvitz, Barbara Conradt

Dartmouth Scholarship

The Caenorhabditis elegans F-box protein SEL-10 and its human homolog have been proposed to regulate LIN-12 Notch signaling by targeting for ubiquitin-mediated proteasomal degradation LIN-12 Notch proteins and SEL-12 PS1 presenilins, the latter of which have been implicated in Alzheimer's disease. We found that sel-10 is the same gene as egl-41, which previously had been defined by gain-of-function mutations that semidominantly cause masculinization of the hermaphrodite soma. Our results demonstrate that mutations causing loss-of-function of sel-10 also have masculinizing activity, indicating that sel-10 functions to promote female development. Genetically, sel-10 acts upstream of the genes fem-1, fem-2, and fem-3 and …