Rsc4 connects the chromatin remodeler RSC to RNA polymerases.
RSC is an essential, multisubunit chromatin remodeling complex. We show here that the Rsc4 subunit of RSC interacted via its C terminus with Rpb5, a conserved subunit shared by all three nuclear RNA polymerases (Pol). Furthermore, the RSC complex coimmunoprecipitated with all three RNA polymerases. Mutations in the C terminus of Rsc4 conferred a thermosensitive phenotype and the loss of interaction with Rpb5. Certain thermosensitive rpb5 mutations were lethal in combination with an rsc4 mutation, supporting the physiological significance of the interaction. Pol II transcription of ca. 12% of the yeast genome was increased or decreased twofold or more in a rsc4 C-terminal mutant. The transcription of the Pol III-transcribed genes SNR6 and RPR1 was also reduced, in agreement with the observed localization of RSC near many class III genes. Rsc4 C-terminal mutations did not alter the stability or assembly of the RSC complex, suggesting an impact on Rsc4 function. Strikingly, a C-terminal mutation of Rsc4 did not impair RSC recruitment to the RSC-responsive genes DUT1 and SMX3 but rather changed the chromatin accessibility of DNases to their promoter regions, suggesting that the altered transcription of DUT1 and SMX3 was the consequence of altered chromatin remodeling.
Soutourina
Julie
J
Service de Biochimie et Génétique Moléculaire, Bâtiment 144, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
Bordas-Le Floch
Véronique
V
Gendrel
Gabrielle
G
Flores
Amando
A
Ducrot
Cécile
C
Dumay-Odelot
Hélène
H
Soularue
Pascal
P
Navarro
Francisco
F
Cairns
Bradley R
BR
Lefebvre
Olivier
O
Werner
Michel
M
D002843:Chromatin / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D021122:Protein Subunits / Q000378:metabolism; D014158:Transcription, Genetic; D015003:Yeasts / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins; D021122:Protein Subunits; D012321:DNA-Directed RNA Polymerases