REVERSIBLE ATTACHMENT OF RNA POLYMERASE TO DNA AS A FUNCTION OF TEMPERATURE

Available observations are in agreement with the idea that RNA polymerase attaches to native DNA at sites that are characterized by weak pairing (Berg et al., 1965; Jones et al., 1966; Maitra et al., 1966; Stent, 1966). If this is the case, we should expect this attachment to be significantly temperature-dependent, since secondary or tertiary structures are more stable at low temperatures (Felsenfeld et al., 1967; Inman, 1966; Follett et al., 1967). The present work brings further arguments in favor of such temperature dependence in agreement with the observations made by Walter et al., 1967). The experimental schemes for determining conditions for attachment employs preincubation at different temperatures in the absence of nucleoside triphosphates. Under these conditions no initiation should occur. On the other hand, when three of the four nucleosides triphosphates are present during preincubation both attachment and initiation must be considered. Although the evidence is indirect, these kinetic experiments do provide information on the initial steps leading up to the transcription. © 1969.