Odyssey EMSA Buffer Kit From LI-COR Biosciences

The Electro Mobility Shift Assay (EMSA) measures transcription factor binding to DNA. Observed differences in DNA binding allow the researcher to determine the effect of transcription factor-DNA activation in response to different treatments. Using the Odyssey Infrared EMSA Kit from LI-COR Biosciences was a simple way to achieve quality results efficiently. The protocol takes the researcher through a 20 to 30 minute reaction set-up followed by a 60 minute gel electrophoresis and 5 minute detection, for a total time of 1.5 hours.

Prior to using the LI-COR’s EMSA kit, I employed a traditional EMSA method using radioactivity. Using radioactivity to detect band shifts required removing the gel from the plates (5 minutes), drying the gel (60 minutes), exposing the gel to x-ray film (up to 48 hours), and finally developing the film (15 minutes). Becoming certified to work with radioactivity took time that could have been used doing research. Since gels are fragile, the process of removing the gel from the plates and drying it often tore the gel. The biggest challenge with the radioactivity method was optimizing the detection time(s). Due to the constantly decaying isotope, exposure times for the same treatment varied, thus making it difficult to reproduce results. Ultimately, one EMSA was taking me days to do, with plenty of troubleshooting. Since I have started using LI-COR’s EMSA kit I can complete an EMSA in about 1.5 hours.

The major time-saving advantage to using this kit comes from being able to image the gel while it is still inside the plates, thus eliminating the time it takes to remove and dry the gel. The five minute, non-radioactive detection is also convenient, simply placing the plate containing the gel on the LI-COR Odyssey scan bed, closing the lid and setting intensity parameters. If the bands are too faint, simply rescan the gel at a higher intensity. The LI-COR Odyssey software has quantifying technology as well. LI-COR’s webpage even has a list of oligos that come pre-made, thus eliminating the need for combining the separate forward and reverse DNA strands. The kit comes with all of the reagents needed to run the EMSA reaction, including reagents for optimizing binding conditions. I have also saved time by purchasing pre-made gels. I have found that Bio-Rad's gel plates are clear and they do not interfere with the detection at all.

The major drawback to the LI-COR EMSA kit is that detecting the bands requires the LI-COR Odyssey, which is an expensive purchase. However, if the researcher is planning on doing a large number of EMSA's, I think it is well worth it. The Odyssey can also be used for quantitative Western blots, also with easy detection which I have found to be superior to chemiluminescence.

Overall, the Odyssey Infrared EMSA Kit form LI-COR Biosciences saves loads of time and yields efficient results through the convenient detection method.