title: RNA Polymerase B levels during the cell cycle ofPhysarum polycephalum.
abstract: Tritiated α-amanitin has been used as a specific and sensitive probe to estimate the number of RNA polymerase B molecules in isolated nuclei, chromatin and nucleoids, obtained from macroplasmodia ofPhysarum polycephalum. During mitosis (metaphase±10 min) there is at least 10-fold less RNA polymerase B than at all phases of the cell cycle, even if DNA replication has been blocked in vivo. It is concluded that many of the RNA polymerase B molecules leave the chromatin during decondensation of the chromosomes in telophase of the synchronous nuclear division ofPhysarum.
authors.affiliation: Zoologisches Institut der Universität, Röntgenring 10, D-8700, Würzburg, Federal Republic of Germany.
authors.forename: Gérard
authors.initials: G
authors.lastname: Pierron
authors.affiliation: Zoologisches Institut der Universität, Röntgenring 10, D-8700, Würzburg, Federal Republic of Germany.
authors.forename: Helmut W
authors.initials: HW
authors.lastname: Sauer
keywords: Cell cycle; Physarum; RNA polymerase B; [3H]α-amanitin binding