Telómeros, secuencias teloméricas intersticiales y aberraciones cromosómicas inducidas por mutágenos químicos

BOLZÁN, A.D.; BIANCHI, M.S.; SÁNCHEZ, J.

Viña del Mar, Chile

Congreso; XIV Congreso Latinoamericano de Genética - VIII Congreso de la Asociación Latinoamericana de Mutagénesis, Carcinogénesis y Teratogénesis Ambiental (ALAMCTA) - XLIII Congreso de la Sociedad de Genética de Chile (SOCHIGEN) y XXXIX Congreso de la SAG; 2010

Asociación Latinoamericana de Genética (ALAG), Asociación Latinoamericana de Mutagénesis, Carcinogénesis y Teratogénesis Ambiental (ALAMCTA), Sociedad de Genética de Chile (SOCHIGEN) y Sociedad Argentina de Genética (SAG)

Telomeres are specialized nucleoproteic complexes localized at the physical ends of linear eukaryotic chromosomes that maintain their stability and integrity, protecting them from degradation, recombination or fusion by preventing the ends of chromosomes from being recognized as double-strand breaks (DSB) by the DNA repair machinery, i.e., they distinguish natural DNA ends from DNA ends resulting from breakage events. Accordingly, when telomeres become dysfunctional, fusions between two telomeres or a telomere and a DSB occur. Therefore, the maintenance of telomere function is crucial for genomic stability and cell viability. By definition, telomeric repeats are located at the very ends or terminal regions of chromosomes. However, some vertebrate species show blocks of (TTAGGG)n repeats present in non-terminal regions of their chromosomes, the so-called interstitial telomeric sequences or ITS, which include those repeats located close to the centromeres and those found at interstitial sites, i.e., between the centromere and the telomere. Using molecular cytogenetics techniques, several types of aberrations involving telomeres and ITS have been identified, including incomplete chromosome elements, acentric fragments, telomeric associations, telomeric fusions and telomeric sister-chromatid exchanges, among others. In this lecture, we will summarize our current knowledge of chromosomal aberrations involving telomeres and ITS and their induction by chemical mutagens in mammalian cells.