this hypothesis was obtained from the interaction of a- 

 amanitin resistant rat fibroblasts (LAN-2) with ADGG-Con A. 

 LAN-2 possess an altered RNA polymerase II with greatly 

 reduced affinity for a-amanitin. Although LAN-2 bind Con 

 A as well as their parent cell line, they were refractory 

 to the toxic effects of ADGG-Con A. 



These experiments demonstrate that covalent conjugates 

 of Con A and a-amanitin retain the biological activity of 

 both portions of the conjugate. Furthermore, the data 

 clearly indicate that Con A permits efficient and specific 

 targeting of amanitin to cells as a function of interaction 

 with specific saccharide receptors on the cell surface. 



VI 



