Novex Quickpoint® (now available from Invitrogen) is a fast and easy acrylamide gel electrophoresis system for separating nucleic acids. It can be used in many applications in place of large sequencing gels such as in RNase protection (RPA), differential display and phage display. The system can also be used to run sequencing reactions where short DNA read lengths (60-80bp) may be sufficient, such as in site directed mutagenesis.
The system has several differences to conventional sequencing gels. The system uses a pH neutral buffer that increases gel stability and allows better resolution of bands when compared to the usual TBE buffer. The most obvious difference between this system and regular sequencing gels is its size and the length of time it takes to run. The pre-cast Novex gels are just 12.5cm long and can be run in 15 minutes, but are capable of resolving 60bp of DNA and RPA products of up to 600bp. Of course the one disadvantage with these gels is that when you need longer DNA read lengths the traditional, larger gels must be used. However, if you want to check a short sequence quickly, the Novex system is ideal. The gels are run in a specially designed mini tank that uses wedges to hold the gels in place, making the whole apparatus less likely to leak than conventional systems. In addition the gel is bonded to one of the glass plates making it easy to handle during fixation and drying. Another advantage is that gels can be dried in the microwave in a few minutes.
I’ve mainly used this system to run RPAs, but have also run one quick sequencing reaction. For both applications the results were good - the bands were sharp and well resolved. But the best thing about the system is that it’s so quick and easy! No more pouring gels, struggling with heavy glass plates and buffer leaking down the back of the gel. Everything is in a compact, easy-to-set-up and use system. Since the gels are pre-cast, it takes only 15 minutes to run and they can be dried in a couple of minutes. A process that used to take me at least half a day has been distilled into less than an hour.
I canvassed a few opinions from others who use this system and everyone that I asked really liked it. The only criticisms were minor and easily overcome. For instance, the wells only hold 1.2ul - for RNase protections you have to solublize your RNA pellet in 2ul of loading dyes and load 0.5ul, which is easier said than done because the pellet becomes sticky. However, this can be solved by increasing the volume of dyes and loading 1ul. One colleague sometimes had trouble drying the gels in a microwave because hot spots can develop and crack the glass plate. But being extra careful to remove the urea by fixing and rinsing well can overcome that problem. And a word of warning: the system is almost too fast. If you turn your back on the gel you can easily run your band of interest off the bottom, so you have to know what you’re looking for and be careful not to get sidetracked while it’s running.
One thing to be aware of is the cost of the system, especially if your lab already has all the equipment for running regular sequencing gels. Initial outlay for the Quickpoint system is about $400 dollars for the tank and free starter kit. New gels cost a little over $20 each, but have only have 16 wells, compared to 32 on larger gels. However, given the amount of time and labor saved and the good results achieved, the system is definitely worth the initial outlay and will be cost-effective in the long run.
Fiona Wardle
Postdoctoral Associate,
Whitehead Institute,
Cambridge, MA