Effects of dNTPs on the SCE frequency in plant root tip cells.

The effects of deoxynucleoside triphosphate (dNTPs) on the frequency of sister-chromatid exchange (SCE) have been studied in plant root tip cells. Treatment with dATP caused a dose-dependent decrease in SCE frequency, while dGTP, caused a dose-dependent increase in SCE frequency both in Hordeum vulgare and in Vicia faba root tip cells. Treatment with dCTP and dTTP significantly increased SCE frequency in H. vulgare root tip cells, but significantly decreased SCE frequency in V. faba root tip cells. The SCE induced by treatment with dGTP could be totally reversed by treatment with an equal concentration of any of the other three dNTPs (dATP, dCTP and dTTP) both in H. vulgare and in V. faba. Treatment with a mixed equal concentration of dATP, dCTP, dGTP and dTTP did not alter the SCE frequency. These results suggest that dNTP pool imbalance is an SCE-affecting factor in plant cells.