TRANSMETHYLATION REACTION IS ESSENTIAL FOR SARCOPHAGA LECTIN GENE ACTIVATION

Incubation of Sarcophaga fat bodies in buffered insect saline resulted in simultaneous activation of multiple defense protein genes [Sugiyam a, H. and Natori, S, (1991) fur. J. Biochem. 200, 495-500]. In this st udy, we demonstrated that the addition of both adenosine and homocyste ine thiolactone to this medium abolished activation of these defense p rotein genes, As S-adenosyl-homocysteine, a potent inhibitor of the tr ansmethylation reaction, is produced in the fat body under these condi tions, methylation of a certain fat body protein seems to be a prerequ isite for the selective activation of insect defense protein genes, Ac tivation of the HSP70 gene was not interfered with S-adenosyl-homocyst eine.