Fast-Painting of Human Metaphase Spreads Using a Chromosome-Specific, Repeat-Depleted DNA Library Probe

For chromosome painting, in situ suppression of repetitive DNA sequences has been well established. Such standard protocols usually require large amounts of Cot-1 DNA®. Recently, it has become possible to deplete repetitive DNA sequences from library probes by magnetic purification and PCR-assisted affinity chromatography. These “repeat-depleted library probes” appear to be extremely useful for Fast-FISH, a technique that omits denaturing chemical agents such as formamide in the hybridization buffer, resulting in a substantial acceleration and simplification of the complete protocol. Shown here is the application of Fast-FISH to a repeat-depleted, directly fluorochrome-labeled library probe of the qarm of chromosome 15 (Fast-Painting) for human lymphocyte metaphase spreads. Following painting without Cot-1 DNA and without formamide, visual inspection revealed sufficient chromosome painting after a few hours of hybridization. The fluorescence signals of the labeling sites were analyzed after hybridization ...