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Articles 451 - 455 of 455

Full-Text Articles in Medical Cell Biology

The Chromokinesin Kid Is Necessary For Chromosome Arm Orientation And Oscillation, But Not Congression, On Mitotic Spindles, Aime A. Levesque, Duane A. Compton Sep 2001

The Chromokinesin Kid Is Necessary For Chromosome Arm Orientation And Oscillation, But Not Congression, On Mitotic Spindles, Aime A. Levesque, Duane A. Compton

Dartmouth Scholarship

Chromokinesins have been postulated to provide the polar ejection force needed for chromosome congression during mitosis. We have evaluated that possibility by monitoring chromosome movement in vertebrate-cultured cells using time-lapse differential interference contrast microscopy after microinjection with antibodies specific for the chromokinesin Kid. 17.5% of cells injected with Kid-specific antibodies have one or more chromosomes that remain closely opposed to a spindle pole and fail to enter anaphase. In contrast, 82.5% of injected cells align chromosomes in metaphase, progress to anaphase, and display chromosome velocities not significantly different from control cells. However, injected cells lack chromosome oscillations, and chromosome orientation …


Eliciting The Low-Activity Aldehyde Dehydrogenase Asian Phenotype By An Antisense Mechanism Results In An Aversion To Ethanol., E Garver, Tu Gc, Q N Cao, M Aini, F Zhou, Y Israel Sep 2001

Eliciting The Low-Activity Aldehyde Dehydrogenase Asian Phenotype By An Antisense Mechanism Results In An Aversion To Ethanol., E Garver, Tu Gc, Q N Cao, M Aini, F Zhou, Y Israel

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

A mutation in the gene encoding for the liver mitochondrial aldehyde dehydrogenase (ALDH2-2), present in some Asian populations, lowers or abolishes the activity of this enzyme and results in elevations in blood acetaldehyde upon ethanol consumption, a phenotype that greatly protects against alcohol abuse and alcoholism. We have determined whether the administration of antisense phosphorothioate oligonucleotides (ASOs) can mimic the low-activity ALDH2-2 Asian phenotype. Rat hepatoma cells incubated for 24 h with an antisense oligonucleotide (ASO-9) showed reductions in ALDH2 mRNA levels of 85% and ALDH2 (half-life of 22 h) activity of 55% equivalent to a >90% inhibition in ALDH2 …


Indistinguishable Nuclear Factor Binding To Functional Core Sites Of The T-Cell Receptor Delta And Murine Leukemia Virus Enhancers., Juan M. Redondo, Jeffrey L. Pfohl, Cristina Hernandez-Munain, Shuwen Wang, Nancy A. Speck, Michael S. Krangel Nov 1992

Indistinguishable Nuclear Factor Binding To Functional Core Sites Of The T-Cell Receptor Delta And Murine Leukemia Virus Enhancers., Juan M. Redondo, Jeffrey L. Pfohl, Cristina Hernandez-Munain, Shuwen Wang, Nancy A. Speck, Michael S. Krangel

Dartmouth Scholarship

We have previously shown that the delta E3 site is an essential element for transcriptional activation by the human T-cell receptor (TCR) delta enhancer and identified two factors, NF-delta E3A and NF-delta E3C, that bound to overlapping core (TGTGGTTT) and E-box motifs within delta E3. In this study, we show that protein binding to the core motif is necessary but not sufficient for transcriptional activation by the delta E3 element. In contrast, protein binding to the E-box motif does not contribute significantly to enhancer activity. A similar core motif present within the enhancers of T-cell-tropic murine retroviruses has been shown …


Interleukin-2-Triggered Raf-1 Expression, Phosphorylation, And Associated Kinase Activity Increase Through G1 And S In Cd3-Stimulated Primary Human T Cells., Antanina Zmuidzinas, Harvey J. Mamon, Thomas M. Roberts, Kendall A. Smith May 1991

Interleukin-2-Triggered Raf-1 Expression, Phosphorylation, And Associated Kinase Activity Increase Through G1 And S In Cd3-Stimulated Primary Human T Cells., Antanina Zmuidzinas, Harvey J. Mamon, Thomas M. Roberts, Kendall A. Smith

Dartmouth Scholarship

To gain further insight into the role of Raf-1 in normal cell growth, c-raf-1 mRNA expression, Raf-1 protein production, and Raf-1-associated kinase activity in normal human T cells were analyzed. In contrast to the constitutive expression of Raf-1 in continuously proliferating cell lines, c-raf-1 mRNA and Raf-1 protein levels were barely detectable in freshly isolated G0 T lymphocytes. Previous work with fibroblasts has suggested that Raf-1 plays a signaling role in the G0-G1 phase transition. In T cells, triggering via the T-cell antigen receptor (TCR)-CD3 complex (TCR/CD3) resulted in an approximately fourfold increase in c-raf-1 mRNA. In addition, the promotion …


K+ Efflux In Nih Mouse 3t3 Cells And Transformed Derivatives: Dependence On Extracellular Ca2+ And Phorbol Esters., Martin Lubin Jul 1988

K+ Efflux In Nih Mouse 3t3 Cells And Transformed Derivatives: Dependence On Extracellular Ca2+ And Phorbol Esters., Martin Lubin

Dartmouth Scholarship

In culture medium deficient in Ca2+, NIH mouse 3T3 cells lose K+, gain Na+, and stop growing. A marked increase in the rate of K+ efflux accounts for this loss; Na+, K+-ATPase pump activity increases but does not fully compensate for enhanced K+ efflux. Phorbol esters and cycloheximide inhibit K+ loss in Ca2+-deficient medium. Phorbol esters inhibit K+ efflux from human fibroblasts as well, even at physiological levels of Ca2+. Two cell lines derived from NIH-3T3, one transformed by a simian virus 40 deletion mutant, the other by the polyoma virus oncogene encoding the middle-sized tumor antigen, retain K+ and …