scholarly journals Mutants in ABC10β, a Conserved Subunit Shared by All Three Yeast RNA Polymerases, Specifically Affect RNA Polymerase I Assembly

1999 ◽  
Vol 274 (13) ◽  
pp. 8421-8427 ◽  
Author(s):  
Olivier Gadal ◽  
George V. Shpakovski ◽  
Pierre Thuriaux
Biochemistry ◽  
1975 ◽  
Vol 14 (22) ◽  
pp. 4907-4911 ◽  
Author(s):  
Joseph Martial ◽  
Josefina Zaldivar ◽  
Paulina Bull ◽  
Alejandro Venegas ◽  
Pablo Valenzuela

1999 ◽  
Vol 19 (1) ◽  
pp. 796-806 ◽  
Author(s):  
Annie-Claude Albert ◽  
Michael Denton ◽  
Milko Kermekchiev ◽  
Craig S. Pikaard

ABSTRACT Mounting evidence suggests that eukaryotic RNA polymerases preassociate with multiple transcription factors in the absence of DNA, forming RNA polymerase holoenzyme complexes. We have purified an apparent RNA polymerase I (Pol I) holoenzyme from Xenopus laevis cells by sequential chromatography on five columns: DEAE-Sepharose, Biorex 70, Sephacryl S300, Mono Q, and DNA-cellulose. Single fractions from every column programmed accurate promoter-dependent transcription. Upon gel filtration chromatography, the Pol I holoenzyme elutes at a position overlapping the peak of Blue Dextran, suggesting a molecular mass in the range of ∼2 MDa. Consistent with its large mass, Coomassie blue-stained sodium dodecyl sulfate-polyacrylamide gels reveal approximately 55 proteins in fractions purified to near homogeneity. Western blotting shows that TATA-binding protein precisely copurifies with holoenzyme activity, whereas the abundant Pol I transactivator upstream binding factor does not. Also copurifying with the holoenzyme are casein kinase II and a histone acetyltransferase activity with a substrate preference for histone H3. These results extend to Pol I the suggestion that signal transduction and chromatin-modifying activities are associated with eukaryotic RNA polymerases.


Biochemistry ◽  
2019 ◽  
Vol 58 (16) ◽  
pp. 2116-2124 ◽  
Author(s):  
Catherine E. Scull ◽  
Zachariah M. Ingram ◽  
Aaron L. Lucius ◽  
David A. Schneider

Isozymes ◽  
1975 ◽  
pp. 69-87
Author(s):  
DAVID H. GRIFFIN ◽  
WILLIAM TIMBERLAKE ◽  
JOHN CHENEY ◽  
PAUL A HORGEN

The activities of the three DNA-dependent RNA polymerases from a rapidly growing rat tumour, Morris hepatoma 3924 A, and from rat liver were examined. The activity of RNA polymerase I was higher in the tumour than in the liver. The enhanced capacity for RNA synthesis was a result of a higher concentration of polymerase I in the tumour as well as of an activation of this enzyme vivo. The possibility that the high specific activity of the hepatoma polymerase I resulted from phosphorylation was investigated. Two major cyclic-AMP-independent nuclear casein kinases (NI and N il) were identified; the activity of protein kinase N il in the tumour was ten times that in liver. Protein kinase N il was capable of activating and phosphorylating RNA polymerase I in vitro . This kinase could also stimulate RNA polymerase II activity, although to a lesser extent than RNA polymerase I. RNA polymerase III was not affected by protein kinase NIL Protein kinase N il was tightly associated with polymerase I and was found even in purified preparations of the polymerase. Antibodies against both RNA polymerase I and protein kinase N il were present in sera of patients with certain rheumatic autoimmune diseases. These results imply that RNA polymerase I and protein kinase NIl are in close association in vivo as well as in vitro and that polymerase phosphorylation may regulate the rate of ribosomal RNA synthesis in the cell.


2003 ◽  
Vol 2 (5) ◽  
pp. 1046-1052 ◽  
Author(s):  
Tatyana Naryshkina ◽  
Adrian Bruning ◽  
Olivier Gadal ◽  
Konstantin Severinov

ABSTRACT The second-largest subunits of eukaryal RNA polymerases are similar to the β subunits of prokaryal RNA polymerases throughout much of their lengths. The second-largest subunits from eukaryal RNA polymerases contain a four-cysteine Zn-binding domain at their C termini. The domain is also present in archaeal homologs but is absent from prokaryal homologs. Here, we investigated the role of the C-terminal Zn-binding domain of Rpa135, the second-largest subunit of yeast RNA polymerase I. Analysis of nonfunctional Rpa135 mutants indicated that the Zn-binding domain is required for recruitment of the largest subunit, Rpa190, into the RNA polymerase I complex. Curiously, the essential function of the Rpa135 Zn-binding domain is not related to Zn2+ binding per se, since replacement of only one of the four cysteine residues with alanine led to the loss of Rpa135 function. Even more strikingly, replacement of all four cysteines with alanines resulted in functional Rpa135.


1993 ◽  
Vol 13 (7) ◽  
pp. 4029-4038
Author(s):  
B M Herschbach ◽  
A D Johnson

The alpha 2 protein of the yeast Saccharomyces cerevisiae normally represses a set of cell-type-specific genes (the a-specific genes) that are transcribed by RNA polymerase II. In this study, we determined whether alpha 2 can affect transcription by other RNA polymerases. We find that alpha 2 can repress transcription by RNA polymerase I but not by RNA polymerase III. Additional experiments indicate that alpha 2 represses RNA polymerase I transcription through the same pathway that it uses to repress RNA polymerase II transcription. These results implicate conserved components of the transcription machinery as mediators of alpha 2 repression and exclude several alternate models.


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