Fig. 8. Rho signaling is involved in mechanisms that protect hemocytes from ISO-induced apoptosis. Transfection of oyster hemocytes with a recombinant plasmid containing the wild-type (hsp rhoWT) or a more active valine-14 mutant (hsp rho V14) Aplysia californica rho gene under the transcriptional control of the gastropod hsp70 gene promoter was able to reduce apoptosis among ISO-treated hemocytes. Control constructs containing the hsp70 gene promoter alone (hsp only) or the rho genes alone (rhoWT only or rhoV14 only) had no significant effect on hemocyte ISO-induced apoptosis. Cells were maintained for 12 hours in the presence of 1 µM ISO or in the absence of drugs (Bas, basal level). Data are means and standard errors of three replicate experiments. Asterisks denote significant (^* for P<0.05, ^** for P<0.01) differences from samples incubated in the presence of ISO alone.