IMBICE   05372
INSTITUTO MULTIDISCIPLINARIO DE BIOLOGIA CELULAR
Unidad Ejecutora - UE
artículos
Título:
Relationship between heterochromatic interstitial telomeric sequences and chromosome damage induced by the radiomimetic compound streptonigrin in Chinese hamster ovary cells.
Autor/es:
SÁNCHEZ J; BIANCHI MS; BOLZÁN AD
Revista:
MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS
Editorial:
Elsevier
Referencias:
Lugar: Netherlands; Año: 2009 vol. 684 p. 90 - 97
ISSN:
0027-5107
Resumen:
The relationship between (heterochromatic) interstitial telomeric sequences (ITSs) and the chromosome
damage induced by the radiomimetic compound streptonigrin (SN) was investigated in Chinese hamster
ovary (CHO) cells by using PNA- and Q-FISH techniques with a pantelomeric probe. CHO cells were
exposed to increasing concentrations of SN and chromosomal aberrations were analyzed in the first mitosis
after treatment. Cytogenetic analysis revealed that 16.9% and 11.7% of the total aberrations induced
by SN in cells harvested 18 h and 3 h after treatment, respectively, exhibited one or more FISH-detectable
telomeric signals. Although there was a significant induction by SN of chromosome breaks at centromeric
regions containing ITSs, about 70% of the chromosome breaks exhibiting telomeric signals observed in SNtreated
cells occurred outside the centromeric regions of chromosomes. This observation, along with the
finding of entirely labeled acentric fragments in both untreated and SN-treated cells show that, although
this antibiotic induces breakage at centromeric regions containing ITSs, thesechromosomeregions are not
the preferential target for the clastogenic action of SN. In addition, our results show that heterochromatic
ITSs are involved more than expected in the formation of chromatid breaks and exchanges induced by
SN, and that these sequences are not preferentially involved in the formation of dicentrics, multicentrics,
centric rings, chromosome breaks, acentric fragments and chromatid deletions induced by this antibiotic.
These findings indicate that the involvement of heterochromatic ITSs in the chromosome damage
induced by SN is not random. Moreover, our results show that SN induces telomeric repeats translocations,
although this effect depends on the concentration of the drug, and that this antibiotic increases
the size of ITSs, this latter effect not being related to the chromosomal sensitivity of the exposed cells to
this compound. The mechanism by which SN induces amplification of heterochromatic ITSs remains to
be elucidated.
© 2009 Published by Elsevier B.V.