INHIBITION OF SV40 DNA-REPLICATION INVITRO BY CHLORPROMAZINE

We examined the inhibitory effect of chlorpromazine, a phenothiazine d erivative, on SV40 DNA replication in a HeLa cell extract. The inhibit ion by chlorpromazine was reversed by cardiolipin, phosphatidylinosito l, phosphatidylglycerol, and phosphatidylserine. Studies on a staged r eaction showed that the pre-elongation step was sensitive to chlorprom azine: chlorpromazine-resistant DNA synthesis was observed when the dr ug was added after the pre-elongation step. Analysis of replication pr oducts by agarose gel electrophoresis revealed that some steps of DNA chain elongation and maturation of closed circular forms were also sen sitive to this drug.