Kinetochore analysis of micronuclei allows insights into the actions of colcemid and mitomycin C.

Abstract

We have induced micronuclei in two strains of diploid human fibroblasts with a known aneugen, colcemid, and a known clastogen, mitomycin C. Using immunofluorescence to detect the presence of kinetochores in micronuclei, we were able to demonstrate a 26.8-fold increase in fluorescence-positive micronuclei (aneuploidy) in colcemid-treated cells. However, colcemid also induced an increase in kinetochore-negative micronuclei. Our findings support previous reports that suggest colcemid may induce chromosome breakage in addition to its major aneugenic effect. The frequency of kinetochore-negative micronuclei (chromosome breakage) in mitomycin C-treated cells rose an average of 7.9-fold in the two test strains, a clear reflection of its clastogenic action. However, a 4-fold increase in the kinetochore-positive fraction was seen. We conclude that the fibroblast micronucleus assay, coupled with kinetochore immunofluorescence, provides a useful screening approach for genotoxic agents. The delineation of the precise mechanism by which an agent perturbs the rates of chromosomal breakage or lag may require more detailed analysis.

• Authors: N L Rudd, S E Williams, M Evans, U G Hennig, D I Hoar
• Journal: Mutation research (Mutat Res) Vol. 261 Issue 1 Pg. 57-68 (Sep 1991) ISSN: 0027-5107 [Print] Netherlands
• PMID: 1908944 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Mitomycins
• Mitomycin
• Demecolcine

Topics

• Aneuploidy
• Chromosome Aberrations
• Demecolcine (pharmacology)
• Evaluation Studies as Topic
• Fibroblasts (ultrastructure)
• Fluorescent Antibody Technique
• Humans
• Micronuclei, Chromosome-Defective (drug effects)
• Mitomycin
• Mitomycins (pharmacology)
• Mutagenicity Tests