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Articles 1 - 30 of 47

Full-Text Articles in Cell and Developmental Biology

Staufen Negatively Modulates Microrna Activity In Caenorhabditis Elegans, Zhiji Ren, Isana Veksler-Lublinsky, David Morrissey, Victor Ambros Mar 2016

Staufen Negatively Modulates Microrna Activity In Caenorhabditis Elegans, Zhiji Ren, Isana Veksler-Lublinsky, David Morrissey, Victor Ambros

Victor R. Ambros

The double-stranded RNA-binding protein Staufen has been implicated in various post-transcriptional gene regulatory processes. Here we demonstrate that the Caenorhabditis elegans homolog of Staufen, STAU-1, functionally interacts with microRNAs. Loss-of-function mutations of stau-1 significantly suppress phenotypes of let-7 family microRNA mutants, a hypomorphic allele of dicer and a lsy-6 microRNA partial loss-of-function mutant. Furthermore, STAU-1 modulates the activity of lin-14, a target of lin-4 and let-7 family microRNAs, and this modulation is abolished when the 3' untranslated region of lin-14 is removed. Deep sequencing of small RNA cDNA libraries reveals no dramatic change in the levels of microRNAs, or other …

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Investigation Of Murine Spleen As A Niche For Hematopoiesis., Jonathan Tan, Helen O'Neill Sep 2015

Investigation Of Murine Spleen As A Niche For Hematopoiesis., Jonathan Tan, Helen O'Neill

Jonathan Tan

Background Spleen as a lymphoid tissue is specialized for monitoring blood and mounting immunity against blood-borne antigens. Antigen-presenting cells present in spleen commonly develop from bone marrow-derived precursors that enter blood circulation. However, a distinct splenic myeloid antigen-presenting cell subset described in this laboratory, namely “dendritic-like cells” (L-DC), has been hypothesized not to share a bone marrow origin. Methods In this study, the presence of endogenous hematopoietic progenitors in spleen was investigated by transplanting intact spleen into allotype-distinct recipients and monitoring development of progeny cells in grafted tissues. Results Successful engraftment of donor spleens was achieved for up to 4 …

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Gene Signature Of Stromal Cells Which Support Dendritic Cell Development., Geneviève Despars, Pravin Periasamy, Jonathan Tan, Janice Abbey, Terence O'Neill, Helen O'Neill Sep 2015

Gene Signature Of Stromal Cells Which Support Dendritic Cell Development., Geneviève Despars, Pravin Periasamy, Jonathan Tan, Janice Abbey, Terence O'Neill, Helen O'Neill

Jonathan Tan

Spleen stromal cells are critical determinants of dendritic cell (DC) development in spleen. The spleen stromal line, namely STX3, supports DC differentiation in vitro from overlaid bone marrow cells while the lymph node stromal line, namely 2RL22, does not. Here we have characterised the hematopoietic support capacity of each stroma, and analyzed lineage origin of the stromal cell lines by gene profiling using microarrays. Stromal co-culture experiments were performed using bone marrow cells as a source of hematopoietic progenitors. A characteristic immature myeloid-like CD11c+CD11b+CD86+MHC-II−/loB220−CD8α− DC is produced after 14 days in STX3 cocultures, while 2RL22 cocultures produce only monocyte/macrophage-like cells. …

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Splenic Stromal Niches Support Hematopoiesis Of Dendritic-Like Cells From Precursors In Bone Marrow And Spleen., Pravin Periasamy, Jonathan Tan, Kristin Griffiths, Helen O'Neill Sep 2015

Splenic Stromal Niches Support Hematopoiesis Of Dendritic-Like Cells From Precursors In Bone Marrow And Spleen., Pravin Periasamy, Jonathan Tan, Kristin Griffiths, Helen O'Neill

Jonathan Tan

Objective The aims of this study are to test the ability of stromal cells from murine spleen to support hematopoiesis, to define the tissue source of precursors that seed these hematopoietic niches, and to determine the type of cells produced. Materials and Methods Cloned isolates of murine spleen stroma have been developed that support hematopoiesis. Analysis has been investigated in terms of tissue source of progenitors. Type and number of cells produced were analyzed by flow cytometry. Results Hematopoietic precursors that seed cocultures exist in spleen and bone marrow (BM), but not thymus. Cell production is highest if overlay cells …

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Hematopoiesis Of Immature Myeloid Dendritic Cells In Stroma-Dependent Spleen Long-Term Cultures Occurs Independently Of Nf-Kb/Relb Function, Jonathan Tan, Keping Ni, Fei Le, Helen O'Neill Sep 2015

Hematopoiesis Of Immature Myeloid Dendritic Cells In Stroma-Dependent Spleen Long-Term Cultures Occurs Independently Of Nf-Kb/Relb Function, Jonathan Tan, Keping Ni, Fei Le, Helen O'Neill

Jonathan Tan

Objective The nuclear factor-κB (NF-KB)/RelB transcription factor plays an essential role in development of some dendritic cell (DC) subsets in mice. In this laboratory, immature myeloid DC are produced in vitro in a stroma-dependent murine spleen long-term culture (LTC) system. In LTC, DC differentiate from hematopoietic progenitors maintained within the stromal cell matrix. Expression and function of RelB in development of LTC-DC has been investigated, with a view to assessing the relationship between DC produced in this system and other known subsets of DC. Materials and Methods RelB expression by LTC-DC was confirmed by detection of protein by Western blotting, …

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Maturation Requirements For Dendritic Cells In T Cell Stimulation Leading To Tolerance Versus Immunity, Helen O'Neill, Jonathan Tan Sep 2015

Maturation Requirements For Dendritic Cells In T Cell Stimulation Leading To Tolerance Versus Immunity, Helen O'Neill, Jonathan Tan

Jonathan Tan

The model that dendritic cell (DC) "maturation" describes the change from an immature, antigen-capturing cell to a mature, antigen-presenting cell is well-established. Classification of DCs in terms of function has been problematic previously. It is therefore proposed that mature and not immature DCs are responsible for antigen presentation and stimulation of T cells. Furthermore, DC antigen presentation to T cells can have two outcomes: tolerance or immunity. The particular outcomes appear to be determined by the activation state of the mature DC. DCs can be activated by a range of environmental stimuli or "danger signals". Here, the hypothesis is advanced …

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Pseudohypoparathyroidism Type 1a And Insulin Resistance In A Child, Benjamin U. Nwosu, Mary M. Lee Sep 2014

Pseudohypoparathyroidism Type 1a And Insulin Resistance In A Child, Benjamin U. Nwosu, Mary M. Lee

Mary M. Lee

Background. A 5-year-old white girl with a history of hypothyroidism in infancy presented to the endocrinology clinic of a tertiary hospital. Her physical examination noted a stocky physique, broad chest, short neck and short digits. Two years later, skin examination revealed subcutaneous nodules and acanthosis nigricans. Investigations. Measurement of levels of serum phosphate, parathyroid hormone, ionized calcium and insulin; measurement of peak growth hormone by the arginine-levodopa stimulation test; calculation of homeostasis model assessment of insulin resistance; assessment of bone age; DNA analysis of the GNAS gene. Diagnosis. Pseudohypoparathyroidism type 1a in a patient with Albright hereditary osteodystrophy, characterized by …

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Multifetal Pregnancy May Increase The Risk For Severe Maternal And Neonatal Vitamin D Deficiency, Benjamin U. Nwosu, Leslie A. Soyka, Amanda Angelescu, Olga T. Hardy, Mary M. Lee Mar 2012

Multifetal Pregnancy May Increase The Risk For Severe Maternal And Neonatal Vitamin D Deficiency, Benjamin U. Nwosu, Leslie A. Soyka, Amanda Angelescu, Olga T. Hardy, Mary M. Lee

Benjamin U. Nwosu

Vitamin D deficiency is prevalent in pregnant women. This deficiency could be exaggerated in multifetal pregnancies by the increased demand on maternal stores of vitamin D. We present 2 cases in which hypocalcemia and secondary hyperparathyroidism occurred in 2 sets of twins from mothers with vitamin D deficiency. The first mother had gastric bypass surgery and Crohn disease. The second mother had no apparent cause of vitamin D deficiency. Both women had iron deficiency anemia and lived in Northeastern United States. We speculate that in twins, the demand for 25-hydroxyvitamin D by 2 fetuses could deplete the 25-hydroxyvitamin D stores …

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Symbiosis (Addiction: Biology, Psychology And Society), Ahmed Mustafa, Sharon Morgillo, Shree Dhawale Dec 2011

Symbiosis (Addiction: Biology, Psychology And Society), Ahmed Mustafa, Sharon Morgillo, Shree Dhawale

Ahmed Mustafa Dr.

No abstract provided.

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Role Of Stat3/5 And Bcl-2/Xl In 2-Methoxyestradiol-Induced Endoreduplication Of Nasopharyngeal Carcinoma Cells, Cm Ting, Ck Wong, Rn Wong, Kw Lo, Aw Lee, Gs Tsao, Ml Lung, N.K. Mak Dec 2010

Role Of Stat3/5 And Bcl-2/Xl In 2-Methoxyestradiol-Induced Endoreduplication Of Nasopharyngeal Carcinoma Cells, Cm Ting, Ck Wong, Rn Wong, Kw Lo, Aw Lee, Gs Tsao, Ml Lung, N.K. Mak

Professor MAK, Nai Ki

2-methoxyestradiol (2ME2), an endogenous metabolite of 17-b-estradiol, has been shown to induce apoptosis and cell cycle arrest in various tumor models. We have previously shown that 2ME2 induced endoreduplication in a welldifferentiated nasopharyngeal carcinoma (NPC) HK-1 and a poorly differentiated C666-1 cell line. In the present study, we studied the survival factors involved in 2ME2-induced endoreduplicating NPC cells. In the HK-1 cells, knockdown of BcL-xL expression by siRNA resulted in the reduction of endoreduplication and an increase in the percentage of apoptosis. Further mechanistic study revealed that 2ME2 enhanced the expression of the phosphorylated form of STAT5 (p-STAT5-Y694), but not …

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Molecular Anatomy Of The Developing Limb In The Coqu ́I Frog, Eleutherodactylus Coqui, Joshua Gross, Ryan Kerney, James Hanken, Clifford Tabin Dec 2010

Molecular Anatomy Of The Developing Limb In The Coqu ́I Frog, Eleutherodactylus Coqui, Joshua Gross, Ryan Kerney, James Hanken, Clifford Tabin

Ryan Kerney

The vertebrate limb demonstrates remark- able similarity in basic organization across phylogenetically disparate groups. To gain further insight into how this mor- phological similarity is maintained in different developmental contexts, we explored the molecular anatomy of size-reduced embryos of the Puerto Rican coqu ́ı frog, Eleutherodactylus coqui. This animal demonstrates direct development, a life- history strategy marked by rapid progression from egg to adult and absence of a free-living, aquatic larva. Nonethe- less, coqu ́ı exhibits a basal anuran limb structure, with four toes on the forelimb and five toes on the hind limb. We in- vestigated the extent to …

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Levels Of Biological Organization And The Origin Of Novelty, Brian Hall, Ryan Kerney Dec 2010

Levels Of Biological Organization And The Origin Of Novelty, Brian Hall, Ryan Kerney

Ryan Kerney

The concept of novelty in evolutionary biology pertains to multiple tiers of biological organization from behavioral and morphological changes to changes at the molecular level. Identifying novel features requires assessments of similarity (homology and homoplasy) of relationships (phylogenetic history) and of shared developmental and genetic pathways or networks. After a brief discussion of how novelty is used in recent literature, we discuss whether the evolutionary approach to homology and homoplasy initially formulated by Lankester in the 19th century informs our understanding of novelty today. We then discuss six examples of morphological features described in the recent literature as novelties, and …

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Embryonic Staging Table For A Direct- Developing Salamander, Plethodon Cinereus (Plethodontidae), Ryan Kerney Dec 2010

Embryonic Staging Table For A Direct- Developing Salamander, Plethodon Cinereus (Plethodontidae), Ryan Kerney

Ryan Kerney

This work presents a refined staging table for the direct-developing red-backed salamander Plethodon cinereus, which is based on the incom- plete staging system of James Norman Dent (J Morphol 1942; 71:577– 601). This common species from eastern North America is a member of the species-rich lungless salamander family Plethodontidae. The stag- ing table presented here covers several stages omitted by Dent and reveals novel developmental features of P. cinereus embryos. These include putative Leydig cells and open gill clefts, which are found in lar- vae of metamorphosing species but were previously reported as absent in direct-developing Plethodon. Other features found …

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Investigation Of Murine Spleen As A Niche For Hematopoiesis., Jonathan Tan, Helen O'Neill Dec 2009

Investigation Of Murine Spleen As A Niche For Hematopoiesis., Jonathan Tan, Helen O'Neill

Helen O'Neill

Background Spleen as a lymphoid tissue is specialized for monitoring blood and mounting immunity against blood-borne antigens. Antigen-presenting cells present in spleen commonly develop from bone marrow-derived precursors that enter blood circulation. However, a distinct splenic myeloid antigen-presenting cell subset described in this laboratory, namely “dendritic-like cells” (L-DC), has been hypothesized not to share a bone marrow origin. Methods In this study, the presence of endogenous hematopoietic progenitors in spleen was investigated by transplanting intact spleen into allotype-distinct recipients and monitoring development of progeny cells in grafted tissues. Results Successful engraftment of donor spleens was achieved for up to 4 …

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Regulatory Elements Of Xenopus Col2a1 Drive Cartilaginous Gene Expression In Transgenic Frogs, Ryan Kerney, Brian K. Hall, James Hanken Dec 2009

Regulatory Elements Of Xenopus Col2a1 Drive Cartilaginous Gene Expression In Transgenic Frogs, Ryan Kerney, Brian K. Hall, James Hanken

Ryan Kerney

This study characterizes regulatory elements of collagen 2α1 (col2a1) in Xenopus that enable transgene expression in cartilage-forming chondrocytes. The reporters described in this study drive strong cartilage-specific gene expression, which will be a valuable tool for further investigations of Xenopus skeletal development. While endogenous col2a1 mRNA is expressed in many embryonic tissues, its expression becomes restricted to tadpole and adult chondrocytes. This chondrocyte-specific expression is recapitulated by col2a1 reporter constructs, which were tested through I-SceI meganuclease-mediated transgenesis. These constructs contain a portion of the Xenopus tropicalis col2a1 intron, which aligns to a cartilage-specific intronic enhancer that has been well characterized …

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Targeted Inhibition Of The Egfr Pathways Enhances Zn-Bc-Am Pdt-Induced Apoptosis In Well-Differentiated Nasopharyngeal Carcinoma Cells, Hk Koon, Ps Chan, Rns Wong, Zg Wu, Ml Lung, Ck Chang, N.K. Mak Dec 2008

Targeted Inhibition Of The Egfr Pathways Enhances Zn-Bc-Am Pdt-Induced Apoptosis In Well-Differentiated Nasopharyngeal Carcinoma Cells, Hk Koon, Ps Chan, Rns Wong, Zg Wu, Ml Lung, Ck Chang, N.K. Mak

Professor MAK, Nai Ki

No abstract provided.

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Skeletal Advance And Arrest In Giant Non-Metamorphosing African Clawed Frog Tadpoles (Xenopus Laevis: Daudin), Ryan Kerney, Richard Wassersug, Brian Hall Dec 2008

Skeletal Advance And Arrest In Giant Non-Metamorphosing African Clawed Frog Tadpoles (Xenopus Laevis: Daudin), Ryan Kerney, Richard Wassersug, Brian Hall

Ryan Kerney

This study examines the skeletons of giant non-metamorphosing (GNM) Xenopus laevis tadpoles, which arrest their development indefinitely before metamorphosis, and grow to excessively large sizes in the absence of detectable thyroid glands. Cartilage growth is isometric; however, chondrocyte size is smaller in GNM tadpoles than in controls. Most cartilages stain weakly with alcian blue, and several cartilages are calcified (unlike con- trols). However, cartilages subjacent to periosteum-derived bone retain strong affinities for alcian blue, indicat- ing a role for periosteum-derived bone in the retention of glycosaminoglycans during protracted larval growth. Bone formation in the head, limb, and axial skeletons is …

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Splenic Stromal Niches Support Hematopoiesis Of Dendritic-Like Cells From Precursors In Bone Marrow And Spleen., Pravin Periasamy, Jonathan Tan, Kristin Griffiths, Helen O'Neill Dec 2008

Splenic Stromal Niches Support Hematopoiesis Of Dendritic-Like Cells From Precursors In Bone Marrow And Spleen., Pravin Periasamy, Jonathan Tan, Kristin Griffiths, Helen O'Neill

Helen O'Neill

Objective The aims of this study are to test the ability of stromal cells from murine spleen to support hematopoiesis, to define the tissue source of precursors that seed these hematopoietic niches, and to determine the type of cells produced. Materials and Methods Cloned isolates of murine spleen stroma have been developed that support hematopoiesis. Analysis has been investigated in terms of tissue source of progenitors. Type and number of cells produced were analyzed by flow cytometry. Results Hematopoietic precursors that seed cocultures exist in spleen and bone marrow (BM), but not thymus. Cell production is highest if overlay cells …

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Mutant Rac1b Expression In Dictyostelium: Effects On Morphology, Growth, Endocytosis, Development, And The Actin Cytoskeleton, S. Palmieri, Thomas Nebl, Robert Pope, D. Seastone, E. Lee, E. Hinchcliffe, Greenfield Sluder, D. Knecht, J. Cardelli, Elizabeth Luna Mar 2008

Mutant Rac1b Expression In Dictyostelium: Effects On Morphology, Growth, Endocytosis, Development, And The Actin Cytoskeleton, S. Palmieri, Thomas Nebl, Robert Pope, D. Seastone, E. Lee, E. Hinchcliffe, Greenfield Sluder, D. Knecht, J. Cardelli, Elizabeth Luna

Elizabeth J. Luna

Rac1 is a small G-protein in the Ras superfamily that has been implicated in the control of cell growth, adhesion, and the actin-based cytoskeleton. To investigate the role of Rac1 during motile processes, we have established Dictyostelium cell lines that conditionally overexpress epitope-tagged Dictyostelium discoideum wild-type Rac1B (DdRac1B) or a mutant DdRac1B protein. Expression of endogenous levels of myc- or GFP-tagged wild-type DdRac1B had minimal effect on cellular morphologies and behaviors. By contrast, expression of a constitutively active mutant (G12-->V or Q61-->L) or a dominant negative mutant (T17-->N) generated amoebae with characteristic cellular defects. The morphological appearance …

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Patellin1, A Novel Sec14-Like Protein, Localizes To The Cell Plate And Binds Phosphoinositides, T. Peterman, Yamini Ohol, Lisa Mcreynolds, Elizabeth Luna Mar 2008

Patellin1, A Novel Sec14-Like Protein, Localizes To The Cell Plate And Binds Phosphoinositides, T. Peterman, Yamini Ohol, Lisa Mcreynolds, Elizabeth Luna

Elizabeth J. Luna

Membrane trafficking is central to construction of the cell plate during plant cytokinesis. Consequently, a detailed understanding of the process depends on the characterization of molecules that function in the formation, transport, targeting, and fusion of membrane vesicles to the developing plate, as well as those that participate in its consolidation and maturation into a fully functional partition. Here we report the initial biochemical and functional characterization of patellin1 (PATL1), a novel cell-plate-associated protein that is related in sequence to proteins involved in membrane trafficking in other eukaryotes. Analysis of the Arabidopsis genome indicated that PATL1 is one of a …

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Identification By Peptide Analysis Of The Spectrin-Binding Protein In Human Erythrocytes, Elizabeth Luna, G. Kidd, D. Branton Mar 2008

Identification By Peptide Analysis Of The Spectrin-Binding Protein In Human Erythrocytes, Elizabeth Luna, G. Kidd, D. Branton

Elizabeth J. Luna

One-dimensional and two-dimensional peptide-mapping techniques are used to identify the protein which gives rise to the 72,000 dalton alpha-chymotryptic fragment previously shown to be the membrane attachment site for spectrin. Peptide maps of the 72,000 dalton fragment are very different from maps of Bands 1, 2, 2.9, 3, 3.1, 4.1, and 4.2 and very similar to maps of the apparently closely homologous polypeptides, Bands 2.1, 2.2, 2.3, and 2.6. Limited proteolysis of erythrocyte membranes is shown to generate Band 3', another polypeptide which has been associated with spectrin-binding activity. Peptide maps of Band 3' are very similar to maps of …

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Direct Binding Of F-Actin To Ponticulin, An Integral Plasma Membrane Glycoprotein, C. Chia, Anne Hitt, Elizabeth Luna Mar 2008

Direct Binding Of F-Actin To Ponticulin, An Integral Plasma Membrane Glycoprotein, C. Chia, Anne Hitt, Elizabeth Luna

Elizabeth J. Luna

We have developed an 125I-labeled F-actin blot overlay assay for the identification of F-actin-binding proteins after transfer to nitrocellulose from SDS-polyacrylamide gels. Two major F-actin-binding proteins from Dictyostelium discoideum, a cytoplasmic 30 kDa protein and a 17 kDa integral membrane protein, and two minor membrane polypeptides of 19 kDa and 15 kDa were detected by this method. Using F-actin affinity and immunoaffinity chromatography, the 17 kDa polypeptide was identified as ponticulin, a previously described actin-binding glycoprotein from D. discoideum plasma membranes (Wuestehube, L.J., and Luna, E.J., [1987]: J. Cell Biol. 105:1741-1751). The binding of F-actin to ponticulin on blots is …

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Merlin Differs From Moesin In Binding To F-Actin And In Its Intra- And Intermolecular Interactions, L. Huang, E. Ichimaru, Kersi Pestonjamasp, X. Cui, H. Nakamura, G. Lo, F. Lin, Elizabeth Luna, H. Furthmayr Mar 2008

Merlin Differs From Moesin In Binding To F-Actin And In Its Intra- And Intermolecular Interactions, L. Huang, E. Ichimaru, Kersi Pestonjamasp, X. Cui, H. Nakamura, G. Lo, F. Lin, Elizabeth Luna, H. Furthmayr

Elizabeth J. Luna

The neurofibromatosis type 2 (NF2) tumor suppressor gene encodes merlin, a protein with homology to the cell membrane/F-actin linking proteins, moesin, ezrin and radixin. Unlike these closely related proteins, merlin lacks a C-terminal F-actin binding site detectable by actin blot overlays, and the GFP-tagged merlin C-terminal domain co-distributes with neither stress fibers nor cortical actin in NIH3T3 cells. Merlin also differs from the other three proteins in its inter- and intramolecular domain interactions, as shown by in vitro binding and yeast two-hybrid assays. As is true for ezrin, moesin and radixin, the N- and C-terminal domains of merlin type 1 …

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A Stable, High Capacity, F-Actin Affinity Column, Elizabeth Luna, Y. Wang, E. Voss, D. Branton, D. Taylor Mar 2008

A Stable, High Capacity, F-Actin Affinity Column, Elizabeth Luna, Y. Wang, E. Voss, D. Branton, D. Taylor

Elizabeth J. Luna

A high capacity F-actin affinity matrix is constructed by binding fluorescyl-actin to rabbit anti-fluorescein IgG that is covalently bound to Sepharose 4B. When stabilized with phalloidin, the actin remains associated with the Sepharose beads during repeated washes, activates the ATPase activity of myosin subfragment 1, and specifically binds 125I-heavy meromyosin and 125I-tropomyosin. The associations between the F-actin affinity matrix and the iodinated F-actin binding proteins are monitored both by affinity chromatography and by a rapid, low speed sedimentation assay. Anti-fluorescein IgG-Sepharose should be generally useful as a matrix for the immobilization of proteins containing accessible, covalently bound fluorescein groups.

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F-Actin And Myosin Ii Binding Domains In Supervillin, Yu Chen, Norio Takizawa, Jessica Crowley, Sang Oh, Cheryl Gatto, Taketoshi Kambara, Osamu Sato, Xiang-Dong Li, Mitsuo Ikebe, Elizabeth Luna Mar 2008

F-Actin And Myosin Ii Binding Domains In Supervillin, Yu Chen, Norio Takizawa, Jessica Crowley, Sang Oh, Cheryl Gatto, Taketoshi Kambara, Osamu Sato, Xiang-Dong Li, Mitsuo Ikebe, Elizabeth Luna

Elizabeth J. Luna

Detergent-resistant membranes contain signaling and integral membrane proteins that organize cholesterol-rich domains called lipid rafts. A subset of these detergent-resistant membranes (DRM-H) exhibits a higher buoyant density ( approximately 1.16 g/ml) because of association with membrane skeleton proteins, including actin, myosin II, myosin 1G, fodrin, and an actin- and membrane-binding protein called supervillin (Nebl, T., Pestonjamasp, K. N., Leszyk, J. D., Crowley, J. L., Oh, S. W., and Luna, E. J. (2002) J. Biol. Chem. 277, 43399-43409). To characterize interactions among DRM-H cytoskeletal proteins, we investigated the binding partners of the novel supervillin N terminus, specifically amino acids 1-830. We …

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Membrane Cytoskeleton: Pip(2) Pulls The Strings, Thomas Nebl, Sang Oh, Elizabeth Luna Mar 2008

Membrane Cytoskeleton: Pip(2) Pulls The Strings, Thomas Nebl, Sang Oh, Elizabeth Luna

Elizabeth J. Luna

A recent application of optical tweezers has shown that plasma membrane phosphatidylinositol 4,5-bisphosphate (PIP(2)) levels control adhesion of the membrane bilayer to the underlying cytoskeleton, by regulated direct binding of PIP(2) to cytoskeletal proteins and/or indirect effects on cytoskeleton structure.

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Gene Signature Of Stromal Cells Which Support Dendritic Cell Development., Geneviève Despars, Pravin Periasamy, Jonathan Tan, Janice Abbey, Terence O'Neill, Helen O'Neill Dec 2007

Gene Signature Of Stromal Cells Which Support Dendritic Cell Development., Geneviève Despars, Pravin Periasamy, Jonathan Tan, Janice Abbey, Terence O'Neill, Helen O'Neill

Helen O'Neill

Spleen stromal cells are critical determinants of dendritic cell (DC) development in spleen. The spleen stromal line, namely STX3, supports DC differentiation in vitro from overlaid bone marrow cells while the lymph node stromal line, namely 2RL22, does not. Here we have characterised the hematopoietic support capacity of each stroma, and analyzed lineage origin of the stromal cell lines by gene profiling using microarrays. Stromal co-culture experiments were performed using bone marrow cells as a source of hematopoietic progenitors. A characteristic immature myeloid-like CD11c+CD11b+CD86+MHC-II−/loB220−CD8α− DC is produced after 14 days in STX3 cocultures, while 2RL22 cocultures produce only monocyte/macrophage-like cells. …

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Detection Of Spliced And Unspliced Forms Of Germline Tcr-Vβ Transcripts In Extrathymic Lymphoid Sites, Janice Abbey, Helen O'Neill Dec 2007

Detection Of Spliced And Unspliced Forms Of Germline Tcr-Vβ Transcripts In Extrathymic Lymphoid Sites, Janice Abbey, Helen O'Neill

Helen O'Neill

Germline TCR-Vβ transcription is commonly considered an event coupled with rearrangement of TCR genes in T cells. The extent of germline Vβ transcription is studied here in a range of cell types and in several mouse strains. A sensitive semi-quantitative RT-PCR method was developed to specifically detect germline and not rearranged transcripts. Germline transcription of a range of different Vβ genes was detected along with rearranged transcripts in bone marrow, thymus, mesenteric lymph node and spleen. Some transcripts were also detected in low level in non-lymphoid tissues including heart, liver and brain. Expression was also studied in the C57BL/6J-β2microglobulin−/− (C57BL/6J-β2M−/−) …

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Hematopoiesis Of Immature Myeloid Dendritic Cells In Stroma-Dependent Spleen Long-Term Cultures Occurs Independently Of Nf-Kb/Relb Function, Jonathan Tan, Keping Ni, Fei Le, Helen O'Neill Dec 2006

Hematopoiesis Of Immature Myeloid Dendritic Cells In Stroma-Dependent Spleen Long-Term Cultures Occurs Independently Of Nf-Kb/Relb Function, Jonathan Tan, Keping Ni, Fei Le, Helen O'Neill

Helen O'Neill

Objective The nuclear factor-κB (NF-KB)/RelB transcription factor plays an essential role in development of some dendritic cell (DC) subsets in mice. In this laboratory, immature myeloid DC are produced in vitro in a stroma-dependent murine spleen long-term culture (LTC) system. In LTC, DC differentiate from hematopoietic progenitors maintained within the stromal cell matrix. Expression and function of RelB in development of LTC-DC has been investigated, with a view to assessing the relationship between DC produced in this system and other known subsets of DC. Materials and Methods RelB expression by LTC-DC was confirmed by detection of protein by Western blotting, …

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Cranial Ontogeny In Philautus Silus (Anura: Ranidae: Rhacophorinae) Reveals Few Similarities With Other Direct-Developing Anurans, Ryan Kerney, Madhava Meegaskumbura, Kelum Manamendra-Arachchi, James Hanken Dec 2006

Cranial Ontogeny In Philautus Silus (Anura: Ranidae: Rhacophorinae) Reveals Few Similarities With Other Direct-Developing Anurans, Ryan Kerney, Madhava Meegaskumbura, Kelum Manamendra-Arachchi, James Hanken

Ryan Kerney

Direct development has evolved in rhaco- phorine frogs independently from other anuran lineages, thereby offering an opportunity to assess features associ- ated with this derived life history. Using a developmen- tal series of the direct-developing Philautus silus (Ranidae: Rhacophorinae) from Sri Lanka, we examine features of cranial morphology that are part of a suite of adaptations that facilitate feeding in free-living tadpoles, but have been changed or lost in other direct-developing lineages. Larval-specific upper jaw cartilages, which are absent from many non-rhacophorine direct-developing species (such as Eleutherodactylus coqui), develop in embryos of P. silus. Similarly, lower jaw cartilages ini- tially …

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