REST-VP16 activates cellular neuronal differentiation genes even in the absence of their normal activating factors. Daoy cells were transfected with pcDNA 3.1, pREST-DBD, pREST, pGal4-VP16, pREST1-VP16 or pREST-VP16, and analyzed by immunocytochemistry using anti-synapsin antibodies. Expression of synapsin was observed only in cells infected with pREST-VP16 and to a lower extent with pREST1-VP16.