Hmo1 is required for TOR-dependent regulation of ribosomal protein gene transcription.
Ribosome biogenesis requires equimolar amounts of four rRNAs and all 79 ribosomal proteins (RP). Coordinated regulation of rRNA and RP synthesis by eukaryotic RNA polymerases (Pol) I, III, and II is a key requirement for growth control. Using a novel global genetic approach, we showed that the absence of Hmo1 becomes lethal when combined with mutations of components of either the RNA Pol II or Pol I transcription machineries, of specific RP, or of the TOR pathway. Hmo1 directly interacts with both the region transcribed by Pol I and a subset of RP gene promoters. Down-regulation of Hmo1 expression affects RP gene expression. Upon TORC1 inhibition, Hmo1 dissociates from ribosomal DNA (rDNA) and some RP gene promoters simultaneously. Finally, in the absence of Hmo1, TOR-dependent repression of RP genes is alleviated. Therefore, we show here that Saccharomyces cerevisiae Hmo1 is directly involved in coordinating rDNA transcription by Pol I and RP gene expression by Pol II under the control of the TOR pathway.
Berger
Axel B
AB
Unité de Biologie Cellulaire du Noyau, Unité de Génétique des Interactions Macromoléculaires, CNRS URA 2171, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris cedex 15, France.
Decourty
Laurence
L
Badis
Gwenaël
G
Nehrbass
Ulf
U
Jacquier
Alain
A
Gadal
Olivier
O
D000903:Antibiotics, Antineoplastic / Q000378:metabolism; D004252:DNA Mutational Analysis; D004275:DNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D006609:High Mobility Group Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases; D012335:RNA, Ribosomal / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D020123:Sirolimus / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D000903:Antibiotics, Antineoplastic; D004275:DNA, Ribosomal; C103154:HMO1 protein, S cerevisiae; D006609:High Mobility Group Proteins; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D017346:Protein Serine-Threonine Kinases; C500749:target of rapamycin protein, S cerevisiae; D012321:DNA-Directed RNA Polymerases; D020123:Sirolimus