Analysis of streptonigrin-induced incomplete chromosome elements and interstitial fragments in Chinese hamster cells using a telomeric PNA probe.
We investigated the induction of incomplete chromosome elements (ICEs; i.e., elements with a telomeric signal at only one terminal end) and interstitial fragments induced by the antibiotic streptonigrin (SN) in a Chinese hamster embryo (CHE) cell line using FISH with a telomeric peptide nucleic acid probe. CHE cells were treated with 0-250 ng/ml SN and chromosomal aberrations were analyzed in the first mitosis after treatment using the telomeric probe. Exposure of CHE cells to SN resulted in a linear concentration-related increase in all of the aberration types analyzed (P < 0.05) except ring chromosomes. Depending on the SN concentration employed, 33-68% of the metaphases contained one or more pairs of ICEs (an incomplete chromosome accompanied by a terminal fragment or two incomplete chromosomes accompanied by a compound fragment). Pooled data from all SN concentrations revealed that 77.8% of the acentric fragments were terminal fragments, 18.8% interstitial fragments, and 3.4% compound fragments. Furthermore, it was estimated that about 80% of excess acentric fragments induced by SN originated from incomplete exchanges or terminal deletions and 20% from complete exchanges (interstitial deletions). These results show that incomplete chromosomes and terminal fragments are the most frequent asymmetrical chromosomal aberrations induced by SN and indicate that true incompleteness is a very common event following exposure to SN.
Laboratorio de Citogenética y Mutagénesis, Instituto Multidisciplinario de Biología Celular, 1900 La Plata, Argentina. abolzan@imbice.org.ar
Alejandro D
AD
Bolzán
Martha S
MS
Bianchi
D000818:Animals; D002869:Chromosome Aberrations / Q000139:chemically induced*; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D017404:In Situ Hybridization, Fluorescence; D015341:Nucleic Acid Probes; D020135:Peptide Nucleic Acids; D013308:Streptonigrin / Q000633:toxicity*; D016615:Telomere / Q000235:genetics*
D015341:Nucleic Acid Probes; D020135:Peptide Nucleic Acids; D013308:Streptonigrin