Structural studies on Neurospora RNA polymerases and associated proteins.
Extensive structural homology between the three nuclear RNA polymerases of Neurospora crassa has been observed by peptide and immunological analyses. Within each polymerase, we found structural similarity between subunits in the 65- to 75-kDa range and one of the two large subunits. We observed also that polymerase II, as isolated, is associated with a 700-kDa complex of 12 polypeptides which is localized in the nucleus. A 75-kDa subunit of the 700-kDa complex was found to be structurally related to the 220-kDa subunit of polymerase II. We suggest, on the basis of the in vitro association, the common nuclear localization and the structural homology, that the 700-kDa complex and polymerase II may be associated in vivo. Evidence is also presented which suggests that polymerase III may interact with chromatin via two of its smallest subunits. A simple procedure for isolating nuclei from Neurospora is described.
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D002467:Cell Nucleus / Q000201:enzymology*; D002843:Chromatin / Q000201:enzymology; D012321:DNA-Directed RNA Polymerases / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D046911:Macromolecular Substances; D008970:Molecular Weight; D009491:Neurospora / Q000201:enzymology*; D009492:Neurospora crassa / Q000201:enzymology*; D010446:Peptide Fragments / Q000032:analysis; D012318:RNA Polymerase I / Q000302:isolation & purification; D012319:RNA Polymerase II / Q000302:isolation & purification; D012320:RNA Polymerase III / Q000302:isolation & purification
D002843:Chromatin; D046911:Macromolecular Substances; D010446:Peptide Fragments; D012319:RNA Polymerase II; D012321:DNA-Directed RNA Polymerases; D012318:RNA Polymerase I; D012320:RNA Polymerase III