The plant ribosome inactivating protein saporin induces micronucleus formation in peripheral human lymphocytes in vitro

Saporin belongs to the family of plant enzymes known as ribosome inactivati ng proteins (RIPs) for their property to depurinate the major rRNA, thus le ading to inactivation of ribosomes. In this work we analyzed the genotoxic effects of saporin, purified from root cultures of Saponaria officinalis, b y evaluating micronucleus formation and by the quantitative determination o f cytosolic histone-associated DNA fragments. Saporin induces micronuclei f ormation in cultured human lymphocytes in a dose dependent manner; treated lymphocytes show a decrease in cell viability and a concomitant increase in the apoptotic response evidenced by the appearance of cytosolic oligonucle osomes. On the other hand saporin treatment failed to induce sister-chromat id exchange (SCE) at any of the doses tested. (C) 1999 Elsevier Science Ire land Ltd. All rights reserved.