title: Polyamines and nucleic acid metabolism in chick embryo. Incorporation of labelled precursors into nucleic acids of subcellular fractions and polyribosomal patterns.
abstract: 1. An increase in polyamine concentration, caused by inhibiting the amine oxidase activities with iproniazid, increased the incorporation of [(3)H]orotic acid into chick-embryo RNA and DNA. On the other hand, a decrease in polyamine concentration, obtained by causing an increase in amine oxidase activities, decreased [(3)H]orotic acid incorporation into nucleic acids. This was particularly evident for nuclear DNA and ribosomal RNA. 2. Polyribosomal patterns obtained by sucrose-density-gradient centrifugation showed highest radioactivity in the regions of 259s and 280s aggregates in those embryos in which the polyamine contents were enhanced, whereas a decrease in the radioactivity was observed when the polyamine concentrations were decreased. 3. The activity of DNA-dependent RNA polymerase, assayed in the same experimental conditions, also varied in the same fashion with changes in polyamine concentration.
authors.affiliation: Istituto di Chimica Biologica dell'Università di Bologna, Bologna, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Moruzzi
authors.forename: B
authors.initials: B
authors.lastname: Barbiroli
authors.forename: C M
authors.initials: CM
authors.lastname: Caldarera