Open AccessMultiple Forms of DNA‐Dependent RNA Polymerase I from Immature Chick Liver
Author(s) -
BIERIBONNIOT Françoise,
DIERKSVENTLING Christa
Publication year - 1977
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1977.tb11344.x
Subject(s) - nucleolus , rna polymerase , polymerase , microbiology and biotechnology , rna , rna polymerase i , biology , rna polymerase ii , rna dependent rna polymerase , dna , chemistry , biochemistry , gene expression , nucleus , gene , promoter
1 We found that a single injection of 17β‐estradiol into immature chicks resulted within 24 h in a 2‐fold increase of the transcriptional capacity of liver nuclei which involved both endogenous RNA polymerase I and II activities. Similarly, RNA polymerase activity I of purified nucleoli was also doubled. 2 During purification of RNA polymerase I from controls and treated chicks the difference in activity was almost completely lost. 3 RNA polymerase I could be resolved into two forms, I A and I B , on CM‐Sephadex. Form I A increased and form I B decreased after estrogen treatment while the sum of the two remained constant. Form I A sedimented more slowly than form I B in glycerol gradients and was predominant in purified nucleoli. 4 These observations suggest that there may be an equilibrium between the two forms of RNA polymerase I which may change in order to produce the translational shift‐up which occurs after estrogen treatment.