Analysis of streptonigrin-induced incomplete chromosome elements and interstitial fragments in Chinese hamster cells using a telomeric PNA probe

BOLZÁN, A.D.; BIANCHI, M.S.

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS

Wiley-Liss, Inc.

Lugar: Wilmington, EE.UU.; Año: 2004 vol. 44 p. 277 - 282

0893-6692

We investigated the induction of incomplete chromosome elements (ICE, i.e., elements with telomeric signal at only one terminal end) and interstitial fragments by the antibiotic streptonigrin (SN) in a Chinese hamster embryo (CHE) cell line using FISH with a telomeric peptide nucleic acid (PNA) 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-response relationship for 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 ICE (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.