Telomerase protects developing neurons against DNA damage-induced cell death

In mitotic cells, telomerase adds repeats of a DNA sequence (TTAGGG) to the ends of chromosomes (telomeres) thereby maintaining their length and preve nting cellular senescence. We recently reported that the catalytic subunit of telomerase (TERT) is expressed in neuronal progenitor cells and in early postmitotic neurons in the developing rodent brain. We now report that TER T can protect cultured PC12 cells and embryonic hippocampal neurons against death induced by DNA damage. Overexpression of TERT in PC12 cells increase s their resistance to the topoisomerase inhibitors camptothecin and etoposi de. Hippocampal neurons in which TERT levels are decreased using antisense technology exhibit increased vulnerability to the DNA-damaging agents. Emer ging findings suggest that DNA damage may trigger the death of neurons duri ng brain development and in neurodegenerative disorders. Our data therefore suggest roles for TERT in modulating such cell deaths. Published by Elsevi er Science B.V.