Proteins gradients

Fosser, K.A., Nuzzo, R.G., Fabrication of patterned multicomponent protein gradients and gradient arrays using microfluidic depletion. Anal. Chem. 2003, 75, 5775-5782. 

Mlodzik, M., Gehring, W.J. 1987. Expression of the caudal gene in the germ line of Drosophila formation of an RNA and protein gradient during early embryogenesis. Cell 48, 465 178. 

Figure 3.10 Concentration gradient of bicoid in the developing fruitfly. Concentration of bicoid protein has been measured in developing embryos as a function of location on the anterior-posterior axis. When present at high levels, biocoid protein activates the gene tailless at intermediate levels, inhibits the gene KruppeC, and activates hunchback. Spatial localization of gene expression is thereby achieved with a simple mechanism for protein-gradient formation.

This can only be considered to be a very brief description, and more comprehensive reviews are available elsewhere (19). A 12.5% polyacrylamide gel is suitable for proteins between 12 and 45 kDa, whereas a 7.5% gel is suitable for 50-150 kDa proteins. Gradient gels allow the separation of most proteins of interest, and can be poured by mixing equal volumes of 5 and 15% acrylamide solutions in a gradient maker. 

Ionov, L., Houbenov, N., Sidorenko, A., Stamm, M., Minko, S. (2009). StimuU-responsive command polymer surface for generation of protein gradients. Biointerphases, 4, FA45-FA49. http //dx.doi.0rg/lO.l 116/1.3119722. 

Kramer, S. et al.. Preparation of protein gradients through the controlled deposition of protein-nanoparticle conjugates onto functionalized surfaces, J. Am. Chem. Soc. 126,5388-95,2004. 

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