Stephanie M. Jung

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MicroRNAs are important regulators of gene expression that control both physiological and pathological processes such as development and cancer. Although their mode of action has attracted great attention, the principles governing their expression and activity are only beginning to emerge. Recent studies have introduced a paradigm shift in our understanding(More)
RNAi is widely applied to inhibit expression of specific genes, but it is limited by variable efficiency and specificity of empirically designed siRNA or shRNA constructs. This complicates studies targeting individual genes and significantly impairs large-scale screens using genome-wide knockdown libraries. Here, we show that ectopic expression of the RISC(More)
Glycoprotein (GP) VI is a platelet membrane protein with a molecular weight of 62 kDa that was identified as a physiological collagen receptor from studies of patients deficient in this protein. GPVI-deficient platelets lacked specifically collagen-induced aggregation and the ability to form thrombi on a collagen surface under flow conditions, suggesting(More)
We have investigated the density of the collagen receptors glycoprotein VI (GPVI) and alpha 2 beta 1 on human platelets and their relationship to polymorphisms within the GPVI gene. GPVI levels varied 1.5-fold and showed a weak correlation (r = 0.35) with the levels of alpha 2 beta 1, which varied 3-fold. GPVI genotype had a significant effect on receptor(More)
Platelet adhesion to the exposed surface of the extracellular matrix in flowing blood is the first and critical reaction for in vivo thrombus formation. However, the mechanism of this in vivo platelet adhesion has yet to be studied extensively. One of the reasons for this is the lack of a practical assay method for assessing platelet adhesion under flow(More)
To examine the relationship between glycoprotein Ib and other proteins in the platelet membrane and the interaction of this protein with thrombin, platelets were crosslinked by two cleavable reagents, SADP (N-succinimidyl(4-azidophenyldithio)propionate) and DTSSP (3,3'-dithiobis(sulfosuccinimidyl propionate]. Two-dimensional, unreduced-reduced sodium(More)
Glycoprotein VI (GPVI) is a platelet-specific glycoprotein that has been indicated to react with collagen and activate platelets. Its structure was recently identified by cDNA cloning (Clemetson, J. M., Polgar, J., Magnenat, E., Wells, T. N., and Clemetson, K. J. (1999) J. Biol. Chem. 274, 29019-29024). However, the mechanism of the interaction between(More)
Glycoprotein VI (GPVI) is an essential platelet collagen receptor; therefore, the inhibition of GPVI-collagen interactions may be an attractive antithrombotic strategy. We have previously shown that targeting of GPVI with antibodies leads to the depletion of the receptor and to long-term antithrombotic protection in mice. An alternative agent to interfere(More)
When platelets are stimulated by agonists, integrin alpha(2)beta(1) (GP Ia/IIa), one of the platelet collagen receptors, is activated to forms with high affinities for its ligand collagen. Here we describe our studies to characterize the binding kinetics of the activated integrin forms and the activation mechanism. Under low agonist concentrations, integrin(More)
Platelet proteins (0.5-5 micrograms) were electrophoresed in a one-dimensional or an unreduced-reduced, two-dimensional sodium dodecyl sulfate gel system. The separated proteins were then transferred electrophoretically to nitrocellulose and reacted with peroxidase-conjugated lectins. Visualization of specific glycoproteins which bound the lectins was made(More)