DNA-dependent RNA polymerases from the integument of blowfly larvae during development and after β-ecdysone action

Abstract DNA-dependent RNA polymerases were extracted from the integument of early third-instar larvae, of pharate pupae, of ligated control, and ligated larvae treated for 150 minutes with 3 C.U. β-ecdysone. Chromatography on DEAE-cellulose revealed the presence of four peaks of RNA polymerase activity, two of which were α-amanitin-resistant (Aa and Ab) and two α-amanitin-sensitive (B and a peak eluting at 0.4 M NH 4 Cl). No quantitative differences were observed in the activity of peaks Aa, Ab, and B between preparations of early third-instar larvae and pharate pupae or between preparations of ligated control and ecdysone-treated larvae. The polymerase eluting at 0.4 M NH 4 Cl, derived from the integument of pharate pupae or ligated ecdysone-injected larvae, showed an increased activity in respect to that of early third-instar larvae of ligated control animals respectively.