Cross-linked DNA as template in the synthesis of RNA in vitro

Abstract

T7 DNA cross-linked by limited treatment with HNO2 or nitrogen mustard can serve as template for RNA synthesis in vitro. At low concentrations, HNO2 does not significantly alter the template activity of the DNA. Nitrogen mustard causes a reduction in template activity although DNA molecules with several cross-links are still active for RNA synthesis. Nitrogen mustard, through monofunctional alkylations, can cause single-strand breaks in DNA; such modifications, more frequent than cross-links, could cause the observed activity loss.T7 DNA, highly cross-linked by HNO2, loses much of its activity for RNA synthesis. This observation is in accord with a mechanism for RNA synthesis which involves at least local strand separation in the DNA template.