Principles of Fluorescence Spectroscopy

730 DNA TECHNOLOGY
Figure 21.52. FISH of a human-hamster hybrid cell. All the chromosomes
are stained uniformly using a nonspecific probe like
DAPI. Three copies of human chromosome 4 were identified by a
probe (yellow) specific for this chromosome. From [150].
Courtesy of Dr. Thomas Ried from the Center for Cancer
Research (NCI/NIH).
can be illustrated by several examples. Figure 21.52 shows
metaphase chromosomes from a human-hamster hybrid cell
line. 150 All the chromosomes were stained with a nonspecific
probe with blue emission. The chromosomes were
exposed to a FISH probe specific for human chromosome 4.
The yellow emission from this probe shows the cell contains
three copies of this chromosome.
FISH can be used to locate individual genes instead of
painting entire chromosomes (Figure 21.53). Methaphase
mouse tumor chromosomes were stained with DNA probes
specific for the immunoglobulin heavy-chain locus (red) or
for the c-myc gene (green). In this case only small regions
of the chromosome are labeled. 150 The interphase nucleus in
the lower right released some of its DNA during sample
preparation. FISH can also be applied to interphase nuclei
when the DNA is not condensed into chromosomes. An
interphase cell was stained with three gene-specific probes,
one with green emission and two with red emission (Figure
21.54). The image shows that the gene labeled with the
green probe is localized between the two other genes.
Figure 21.53. Mouse tumor metaphase chromosomes stained for the
immunoglobulin heavy chain locus (red) and the c-myc gene (green).
All the DNA was stained with a nonspecific blue fluorophore. Image
courtesy of Dr. Thomas Ried from the Center for Cancer Research
(NCI/NIH).
21.8. MULTICOLOR FISH AND
SPECTRAL KARYOTYPING
Suppose it is necessary to identify each of the chromosomes
by staining with FISH probes. Because of the width of the
emission from most fluorophores it is not possible to visually
identify more than about five fluorophores. Identifica-
Figure 21.54. Labeling of an interphase nucleus with three gene-specific
probes. Images courtesy of Dr. Thomas Ried from the Center for
Cancer Research (NCI/NIH).