Assessing LINE-1 retrotransposition activity in neuroblastoma cells exposed to extremely low-frequency pulsed magnetic fields.

Mobile genetic elements represent an important source of mutation and genomic instability, and their activity can be influenced by several chemical and physical agents. In this research we address the question whether exposure to extremely low-frequency pulsed magnetic fields (EMF-PMF) could affect the mobility of the human LINE-1(RP) retrotransposon. To this purpose, an in vitro retrotransposition assay was used on human neuroblastoma BE(2) cells exposed for 48h to 1mT, 50Hz PMF, or sham-exposed. Moreover, since it is well known that retrotransposition causes DNA double-strand breaks (DSB), an estimation of γ-H2AX foci, which is a marker of DNA DSB, was carried out on PMF- and sham-exposed samples. The results show that PMF-exposed cells had a lower number of both retrotransposition events and DNA DSB compared with sham-exposed samples. These results suggest that exposure to PMF can interfere with retrotransposition activity by inducing a decrease of retrotransposition events.