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Articles 121 - 132 of 132

Full-Text Articles in Molecular Biology

A Feedback Circuit Involving Let-7-Family Mirnas And Daf-12 Integrates Environmental Signals And Developmental Timing In Caenorhabditis Elegans, Christopher M. Hammell, Xantha Karp, Victor R. Ambros Nov 2009

A Feedback Circuit Involving Let-7-Family Mirnas And Daf-12 Integrates Environmental Signals And Developmental Timing In Caenorhabditis Elegans, Christopher M. Hammell, Xantha Karp, Victor R. Ambros

Victor R. Ambros

Animal development is remarkably robust; cell fates are specified with spatial and temporal precision despite physiological and environmental contingencies. Favorable conditions cause Caenorhabditis elegans to develop rapidly through four larval stages (L1-L4) to the reproductive adult. In unfavorable conditions, L2 larvae can enter the developmentally quiescent, stress-resistant dauer larva stage, enabling them to survive for prolonged periods before completing development. A specific progression of cell division and differentiation events occurs with fidelity during the larval stages, regardless of whether an animal undergoes continuous or dauer-interrupted development. The temporal patterning of developmental events is controlled by the heterochronic genes, whose products …

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Bmp Signaling Goes Posttranscriptional In A Microrna Sort Of Way, Catherine A. Reinke, Richard W. Carthew Jan 2008

Bmp Signaling Goes Posttranscriptional In A Microrna Sort Of Way, Catherine A. Reinke, Richard W. Carthew

Faculty Publications

Aberrant microRNA (miRNA) expression correlates with human diseases such as cardiac disorders and cancer. Treatment of such disorders using miRNA-targeted therapeutics requires a thorough understanding of miRNA regulation in vivo. A recent paper in Nature by Davis et al. expands our understanding of miRNA biogenesis and maturation, elucidating a mechanism by which extracellular signaling directs cell differentiation via posttranscriptional regulation of miRNA expression.

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A Molecular Phylogeny Of The Genus Bonamia Based On Sequence Data Of The Ribosomal Rna (Rrna) Gene Complex, Delonna M. White Jan 2008

A Molecular Phylogeny Of The Genus Bonamia Based On Sequence Data Of The Ribosomal Rna (Rrna) Gene Complex, Delonna M. White

Dissertations, Theses, and Masters Projects

No abstract provided.

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Eph Receptors And Ephrins, Masaru Nakamoto Jan 2000

Eph Receptors And Ephrins, Masaru Nakamoto

Biology Faculty Publications

The Eph receptors are the largest known family of receptor tyrosine kinases. The Eph receptors and theirmembrane-attached ligands, ephrins, show diverse expression patterns during development. Recent studies havedemonstrated that Eph receptors and ephrins play important roles in many developmental processes, includingneuronal network formation, the patterning of the neural tube and the paraxial mesoderm, the guidance of cellmigration, and vascular formation. In the nervous system, Eph receptors and ephrins have been shown to act aspositional labels to establish topographic projections. They also play a key role in pathway ®nding by axons andneural crest cells. The crucial roles of Eph receptors and …

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Leukemia Inhibitory Factor (Lif): Murine Preimplantation Embryo Development, Implantation Rates, And Skeletal Development, Michael Hayes Mitchell Jul 1998

Leukemia Inhibitory Factor (Lif): Murine Preimplantation Embryo Development, Implantation Rates, And Skeletal Development, Michael Hayes Mitchell

Theses and Dissertations in Biomedical Sciences

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine which demonstrates perplexing physiological effects. It has been demonstrated that LIF is essential for implantation in mice. Little is known relating to the manner by which LIF effects pre-implantation and post-implantation development. The objectives of this project were to determine the effects LIF on pre-implantation development, to determine the effects that it may have on implantation rates, successful pregnancy rates, and resorption rates, and to determine the effects that LIF has on the skeletal development of mice. For the embryo transfer experiments, embryos were exposed to test compounds in the transfer medium …

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Phylogeny Of The Haplosporidia (Eukaryota: Alveolata) Based On Small Subunit Ribosomal Rna Gene Sequence, Brenda Sandy Flores Jan 1996

Phylogeny Of The Haplosporidia (Eukaryota: Alveolata) Based On Small Subunit Ribosomal Rna Gene Sequence, Brenda Sandy Flores

Dissertations, Theses, and Masters Projects

No abstract provided.

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Complementary Gradients In Expression And Binding Of Elf-1 And Mek4 In Development Of The Topographic Retinotectal Projection Map, Masaru Nakamoto Jan 1995

Complementary Gradients In Expression And Binding Of Elf-1 And Mek4 In Development Of The Topographic Retinotectal Projection Map, Masaru Nakamoto

Biology Faculty Publications

Topographic maps with a defined spatial ordering of neuronal connections are a key feature of brain organization. Such maps are believed to develop in response to complementary position-specific labels in presynaptic and postsynaptic fields. However, the complementary labeling molecules are not known. In the well studied visual map of retinal axons projecting to the tectum, the labels are hypothesized to be in gradients, without needing large numbers of cell-specific molecules. We recently cloned ELF-1 as a ligand for Eph family receptors. Here, RNA hybridization shows matching expression gradients for ELF-1 in the tectum and its receptor Mek4 in the retina. …

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Cell Surface-Binding Sites For Progesterone Mediate Calcium Uptake In Human Sperm, Peter F. Blackmore, Joseph Neulan, Frank Lattanzio, Stephen J. Beebe Jan 1991

Cell Surface-Binding Sites For Progesterone Mediate Calcium Uptake In Human Sperm, Peter F. Blackmore, Joseph Neulan, Frank Lattanzio, Stephen J. Beebe

Bioelectrics Publications

Recent studies (e.g. Blackmore, P. F., Beebe, S. J., Danforth, D. R., and Alexander, N.) (1990) J. Biol. Chem. 265, 1376-1380) have shown that in human sperm, progesterone produces a rapid increase in intracellular free calcium ([Ca2+]i) and an induction of the acrosome reaction (e.g. Osman, R. A., Andria, M. L., Jones, A. D., and Meizel, S. (1989) Biochem. Biophys. Res. Commun. 160, 828-833). In this study, the location of progesterone receptors on the cell surface of human sperm was identified using progesterone immobilized on bovine serum albumin (BSA) (progesterone 3-(O-carboxymethyl)oxime:BSA) as well as progesterone and its 3-O-carboxymethyloxime derivative. Using …

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Laminin Potentiates Differentiation Of Pcc4uva Embryonal Carcinoma Into Neurons, T. M. Sweeney, Roy C. Ogle, C. D. Little Sep 1990

Laminin Potentiates Differentiation Of Pcc4uva Embryonal Carcinoma Into Neurons, T. M. Sweeney, Roy C. Ogle, C. D. Little

Medical Diagnostics & Translational Sciences Faculty Publications

The embryonal carcinoma PCC4uva differentiates into neurons in response to treatment with retinoic acid and dbcAMP. We used this in vitro model system to study the effects of laminin on early neural differentiation. Laminin substrata markedly potentiate neural differentiation of retinoic acid and dbcAMP-treated cultures. Only laminin induced more rapid neural cell body clustering, neurite growth and neurite fasciculation as compared to type IV collagen, type I collagen, and fibronectin substrata. Exogenous laminin substrata promoted greater cell attachment, cellular spreading and growth to confluence than type IV collagen, type I collagen, fibronectin and glass substrata. Laminin-induced effects were inhibited by …

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A Retinoic Acid Responsive Gene, Mk, Produces A Secreted Protein A With Heparin Binding Activity, Masaru Nakamoto Jan 1990

A Retinoic Acid Responsive Gene, Mk, Produces A Secreted Protein A With Heparin Binding Activity, Masaru Nakamoto

Biology Faculty Publications

MK is a gene whose expression increases transiently during retinoic acid-induced differentiation of embryonal carcinoma cells. MK polypeptide was secreted by differentiating HM-1 embryonal carcinoma cells and by L-cells transfected with an MK cDNA under the control of the S-actin promoter and Rous sarcoma virus enhancer. MK polypeptide was found to have heparin binding activity. Conditioned medium of the transfected L-cells promoted growth of PC-12 pheochromocytoma cells. These findings support the view that MK polypeptide is a secreted factor involved in regulation of growth and differentiation.

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Collagen Binding Proteins Derived From The Embryonic Fibroblast Cell Surface Recognize Arginine-Glycine-Aspartic Acid, Roy C. Ogle, Charles D. Little Jun 1989

Collagen Binding Proteins Derived From The Embryonic Fibroblast Cell Surface Recognize Arginine-Glycine-Aspartic Acid, Roy C. Ogle, Charles D. Little

Medical Diagnostics & Translational Sciences Faculty Publications

Several cell surface proteins (Mr = 120,000, 90,000, 63,000 and 47,000) apparently integral to embryonic fibroblast plasma membranes were extracted with detergent and isolated by collagen affinity chromatography. Certain of these proteins (Mr = 120,000, 90,000, and 47,000) were specifically eluted from collagen affinity columns by synthetic peptides containing the amino acid sequence arginyl-glycyl-aspartic acid (RGD). These data show that a number of collagen binding proteins exist on the embryonic fibroblast cell surface. Some of the proteins may be collagen receptors binding to RGD sequences in the collagen molecule while at least one of the proteins (Mr = 63,000) recognizes …

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Laminin Receptors For Neurite Formation, H. K. Kleinman, Roy C. Ogle, F. B. Cannon, C. D. Little, T. M. Sweeney, L. Luckenbill-Edds Feb 1988

Laminin Receptors For Neurite Formation, H. K. Kleinman, Roy C. Ogle, F. B. Cannon, C. D. Little, T. M. Sweeney, L. Luckenbill-Edds

Medical Diagnostics & Translational Sciences Faculty Publications

Laminin, a basement membrane glycoprotein promotes both cell attachment and neurite outgrowth. Separate domains on laminin elicit these responses, suggesting that distinct receptors occur on the surface of cells. NG108-15 neuroblastoma-glioma cells rapidly extend long processes in the presence of laminin. We report here that 125I-labeled laminin specifically binds to these cells and to three membrane proteins of 67, 110, and 180 kDa. These proteins were isolated by affinity chromatography on laminin-Sepharose. The 67-kDa protein reacted with antibody to the previously characterized receptor for cell attachment to laminin. Antibodies to the 110-kDa and 180-kDa bands demonstrated that the 110-kDa protein …

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