A general suppressor of RNA polymerase I, II and III mutations in Saccharomyces cerevisiae.
A multicopy genomic library of Saccharomyces cerevisiae (strain FL100) was screened for its ability to suppress conditionally defective mutations altering the 31 kDa subunit (rpc31-236) or the 53 kDa subunit (rpc53-254/424) of RNA polymerase III. In addition to allele-specific suppressors, we identified seven suppressor clones that acted on both mutations and also suppressed several other conditional mutations defective in RNA polymerases I or II. All these clones harbored a complete copy of the SSD1 gene. The same pleiotropic suppression pattern was found with the dominant SSD1-v allele present in some laboratory strains of S. cerevisiae. SSD1-v was previously shown to suppress mutations defective in the SIT4 gene product (a predicted protein phosphatase subunit) or in the regulatory subunit of the cyclic AMP-dependent protein kinase. We propose that the SSD1 gene product modulates the activity (or the level) of the three nuclear RNA polymerases, possibly by altering their degree of phosphorylation.
Stettler
S
S
Département de Biologie Cellulaire et Moléculaire, C.E.A. Centre d'Etudes de Saclay, Gif sur Yvette, France.
Chiannilkulchai
N
N
Hermann-Le Denmat
S
S
Lalo
D
D
Lacroute
F
F
Sentenac
A
A
Thuriaux
P
P
D000483:Alleles; D005656:Fungal Proteins / Q000235:genetics*; D005800:Genes, Fungal; D012318:RNA Polymerase I / Q000235:genetics*; D012319:RNA Polymerase II / Q000235:genetics*; D012320:RNA Polymerase III / Q000235:genetics*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D013489:Suppression, Genetic
D005656:Fungal Proteins; D012319:RNA Polymerase II; D012318:RNA Polymerase I; D012320:RNA Polymerase III