DETECTION OF HYDROQUINONE-INDUCED NONRANDOM BREAKAGE IN THE CENTROMERIC HETEROCHROMATIN OF MOUSE BONE-MARROW CELLS USING MULTICOLOR FLUORESCENCE IN-SITU HYBRIDIZATION WITH THE MOUSE MAJOR AND MINOR SATELLITE PROBES
Hw. Chen et al., DETECTION OF HYDROQUINONE-INDUCED NONRANDOM BREAKAGE IN THE CENTROMERIC HETEROCHROMATIN OF MOUSE BONE-MARROW CELLS USING MULTICOLOR FLUORESCENCE IN-SITU HYBRIDIZATION WITH THE MOUSE MAJOR AND MINOR SATELLITE PROBES, Mutagenesis, 9(6), 1994, pp. 563-569
Fluorescence in situ hybridization with a mouse major satellite probe
and CREST staining were used to characterize the origin of micronuclei
occurring in mouse bone marrow erythrocytes following administration
of the benzene metabolite hydroquinone. Hydroquinone was administered
to male CD-1 mice by i.p. injection on three consecutive days and the
bone marrow cells were harvested 24 h later. A pronounced difference i
n the results was observed using the two approaches: 63% of the micron
uclei induced by hydroquinone labeled with the major satellite probe w
hereas only 28% labeled with the CREST antibody. To determine whether
the observed difference was due to a disruption of the kinetochore or
a result of breakage within centromeric heterochromatin, we developed
a tandem label multicolor hybridization assay, which requires the pres
ence of both the mouse major and minor satellite probes in a micronucl
eus for a classification of chromosomal loss. The minor probe targets
a centromeric region physically linked to the short arm of mouse chrom
osomes, whereas the major probe hybridizes to the centromeric heteroch
romatin adjacent to the long arm. Using this approach, 29% of the micr
onuclei induced by hydroquinone hybridized with both the major and min
or satellite probes, indicating chromosome loss; an additional 37% lab
eled with only the major satellite probe indicating breakage within th
e centromeric heterochromatin. Although the region targeted by the maj
or satellite probe comprises only 5-10% of the mouse genome, these maj
or-probe containing micronuclei represent 53% of the micronuclei forme
d as the result of chromosome breakage. These results indicate that, i
n addition to chromosome loss and breakage throughout the euchromatin,
hydroquinone induces nonrandom breakage within the centromeric hetero
chromatin. This new hybridization assay shows promise as an accurate t
echnique for distinguishing micronuclei arising from chromosome loss f
rom those originating from chromosome breakage, particularly when brea
kage occurs within the mouse heterochromatin, a breakage-prone region
targeted by the major satellite probe.