Article révisé par les pairs
Résumé : The transcription of globin genes in mouse foetal liver chromatin and nuclei by exogenous Escherichia coli RNA polymerase is prone to artifacts due to RNA-dependent transcription of endogenous mRNA sequences. This is particularly evident when Mn2+ is used as divalent cation in the RNA transcription reaction. However, substitution or supplementation with Mg2+ eliminates this artifact and gives essentially asymmetric DNA-dependent transcription by the polymerase. In this paper we discuss a number of general criteria which can be applied to test the validity of specific gene transcription in vitro.