Purification of Yeast Artificial Chromosome DNA for Microinjection Using a Two-Gel Electrophoresis Procedure

Large-Scale Preparation of Yeast Agarose Plugs to Isolate Yeast Artificial Chromosome DNA

The microinjection of DNA directly into the pronuclei of fertilized zygotes is the most extensively used method of gene transfer in the mouse. The injection of very large pieces of DNA, including bacterial artificial chromosomes (BACs) and yeast artificial chromosomes (YACs), has become increasingly popular because their size normally accommodates all of the regulatory elements that are needed for a given expression domain to function adequately in an ectopic genomic location. This protocol describes how to prepare large-scale yeast agarose plugs to isolate YAC DNA. The quality of the YAC DNA preparation is the most important consideration in optimizing transgenic mouse production.

Purification of Yeast Artificial Chromosome DNA for Microinjection Using Pulsed-Field Gel Electrophoresis and Ultrafiltration

This protocol describes a method for concentrating yeast artificial chromosome (YAC) DNA preparations following separation of chromosomes by pulsed-field gel electrophoresis (PFGE). The agarose slice containing the YAC DNA of interest is melted and digested. The resulting YAC DNA-containing solution is concentrated using ultrafiltration units with a 30,000-mwt cutoff. The DNA is retained in the upper container, where it concentrates sixfold to sevenfold. Ideally, YAC DNA preparations at 10-60 ng/µL can be obtained. However, great care must be taken to recover the YAC DNA molecules that sometimes irreversibly attach to the filter membrane. This procedure can also be used to concentrate BAC DNA from PFGE gel slices of BAC DNA-containing agarose exactly as described for YACs.