Centromere-Specific Multicolor-FISH (cenM-FISH)

Abstract

24-color FISH using five different fluorochromes has recently been described as M-FISH or SKY, and is a useful technique for the characterization of complex chromosomal aberrations (Speicher et al., 1996; Schröck et al, 1996; for an overview of multicolor-FISH literature see http://mtin.mti.uni-jena.de/~huwww/Mol_ZYTO/mFISHlit.htm). For technical reasons whole or partial chromosome libraries, each specific for an entire chromosome, exclude the centromeric regions of the color staining due to the blocking of repetitive sequences by COT 1-DNA. Here, we describe a recently developed new multicolor FISH technique — called centromerespecific multicolor-FISH (cenM-FISH) (Nietzel et al. 2001). The technique is based on all available centromere-specific DNA probes, which are labeled in five different fluorochromes (i.e. TexasRed, SpectrumGreen, SpectrumOrange, Cy5 and DEAC) according to Fig. IB and hybridized simultaneously. This approach allows the identification of all human centromeres by their individual coloring in one single step and therefore is a powerful tool in molecular cytogenetics. Centromere-specific multicolor FISH is a very helpful technique especially for the characterization of small marker chromosomes with no — or nearly no — euchromatin and small amounts of available chromosome suspension (see Fig. 1A).