Bio-Rad’s Mini-PROTEAN 3 Dodeca Cell is very convenient as far as 2-dimensional gel electrophoresis is concerned. The apparatus is ideal for high throughput separation of proteins. It is the best system available for running such a large number of gels at a time in a single apparatus. The alternative would be to use 6 minigel systems, however, running gels simultaneously on multiple systems becomes extremely tedious and time consuming. The Dodeca Cell separates proteins well and because of its ability to maintain constant temperature (because of the stir bar capability) over the whole apparatus, it gives a sharp and straight dye front, which can help in determining the proper molecular weight of the protein. Our lab does not use an external refrigerated coolant, which helps in cooling the buffer as the run proceeds, because it does not make a difference in the separation of proteins with our infrastructure. We do observe a “smiling effect” when we use the apparatus without cooling. The system requires 3 to 3.5 liters of buffer for 6-12 gels to be run at a time and it is convenient for separation of proteins in the first dimension.
The Mini-PROTEAN 3 Dodeca Cell is currently used in our lab for the separation of cytokeratins. Cytokeratins are epithelia-specific intermediate filament proteins, which exhibit post-translational modifications. They are a family of proteins, which have molecular weights ranging from 40kD to 67kD. Many different cytokeratins have the same/close molecular weights, but different isoelectric points. Hence separation by 2D electrophoresis becomes essential for the clear identification of cytokeratins. A stratified tumor cell line that we have developed exhibits all of the simple epithelial keratins along with some of the stratified epithelial keratins. Identifying the individual keratins was possible with the Mini-PROTEAN 3 Dodeca Cell. Using this system, we were able to perform high throughput separation of cytokeratins with nice reproducibility and in the least amount of time.
The Mini-PROTEAN 3 Dodeca Cell is compatible with powerpacks available from Bio-Rad: PowerPac HC and PowerPac Universal. For 2D electrophoresis, seven cm strips of varying pH gradients are also available from Bio-Rad. It is simple to apply a molecular weight marker onto filter paper and place it in contact with the gel. The marker can then vertically migrate into the gel. However, sometimes the marker will diffuse into the gel and produce a horizontal line. To avoid this, we cool the agarose for awhile prior to placing the marker paper in contact with the gel. Unfortunately, sometimes the agarose solidifies making it difficult for the marker paper to be inserted. Hence, it would be helpful if a technology could be developed which can inhibit the diffusion of the marker into the area used for analysis.
A non-breakable substitute for glass, one which exhibits resistance to increases in temperature, would make this system ideal. Currently, even when proper precautions are taken, the glass plates break. Plates are the main consumable for the Mini-PROTEAN 3 Dodeca Cell. Otherwise, system maintenance is simple.
The apparatus is fairly compact and requires minimum space. It would have been a mess to use 6 apparatuses (assuming one apparatus runs 2 gels) in place of this one. The assembly is user friendly and one can learn it in no time.
Bio-Rad’s Mini-PROTEAN 3 Dodeca Cell will be useful to researchers who are investigating alterations in the proteomes of altered cells. The identification of reliable tumor markers for many cancers is another challenge faced by biologists. Bio-Rad’s Mini-PROTEAN 3 Dodeca Cell would enable biologists to identify novel proteins associated with the diseased phenotype.
Deepak Kanojia
Senior Research Fellow
Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), TMC.
Department of Biochemistry and Cell Biology