Mimosine is a potent clastogen in primary and transformed hamster fibroblasts but not in primary or transformed human lymphocytes.

The cytogenetic effects of mimosine, a naturally occurring plant amino acid known to arrest cell-cycle progression at the G1-S border in cultured cells, have been studied. It was found that mimosine inhibits the cell-cycle progression in a dose-dependent manner in primary and transformed Chinese hamster fibroblasts as well as primary lymphocytes and transformed lymphoblastoid cells of human origin. In the Chinese hamster fibroblast cells, the first division metaphases analysed were found to be highly damaged or pulverized. The damaged cells which could pass through the next cell division, showed very high frequencies of sister chromatid exchanges (SCEs) compared with untreated second division cells. No such cytogenetic alterations could be detected in the human cells. The absence of clastogenic effect in cells of lymphoid origin appears to be related to the known capacity of these cells to undergo apoptosis, thereby efficiently eliminating cells with high frequencies of chromosomal aberrations. Our study demonstrates the clastogenic potency of mimosine and suggests the need for a careful interpretation of the results while using mimosine for cellular or molecular studies pertaining to cell cycle events.