title: A chemical-genetic screen to unravel the genetic network of CDC28/CDK1 links ubiquitin and Rad6-Bre1 to cell cycle progression.
abstract: Cyclin-dependent kinases (CDKs) control the eukaryotic cell cycle, and a single CDK, Cdc28 (also known as Cdk1), is necessary and sufficient for cell cycle regulation in the budding yeast Saccharomyces cerevisiae. Cdc28 regulates cell cycle-dependent processes such as transcription, DNA replication and repair, and chromosome segregation. To gain further insight into the functions of Cdc28, we performed a high-throughput chemical-genetic array (CGA) screen aimed at unraveling the genetic network of CDC28. We identified 107 genes that strongly genetically interact with CDC28. Although these genes serve multiple cellular functions, genes involved in cell cycle regulation, transcription, and chromosome metabolism were overrepresented. DOA1, which is involved in maintaining free ubiquitin levels, as well as the RAD6-BRE1 pathway, which is involved in transcription, displayed particularly strong genetic interactions with CDC28. We discovered that DOA1 is important for cell cycle entry by supplying ubiquitin. Furthermore, we found that the RAD6-BRE1 pathway functions downstream of DOA1/ubiquitin but upstream of CDC28, by promoting transcription of cyclins. These results link cellular ubiquitin levels and the Rad6-Bre1 pathway to cell cycle progression.
authors: Department of Molecular Biology, Institute of Medical Microbiology and Centre of Molecular Biology and Neuroscience,  Oslo University Hospital, N-0027 Oslo,  Norway.
authors: Christine
authors: C
authors: Zimmermann
authors: Pierre
authors: P
authors: Chymkowitch
authors: Vegard
authors: V
authors: Eldholm
authors: Christopher D
authors: CD
authors: Putnam
authors: Jessica M
authors: JM
authors: Lindvall
authors: Manja
authors: M
authors: Omerzu
authors: Magnar
authors: M
authors: Bjørås
authors: Richard D
authors: RD
authors: Kolodner
authors: Jorrit M
authors: JM
authors: Enserink
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000483:Alleles; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D002453:Cell Cycle; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D005800:Genes, Fungal; D008957:Models, Genetic; D012097:Repressor Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C472168:Bre1 protein, S cerevisiae; C099944:DOA1 protein, S cerevisiae; C497163:Lge1 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D025801:Ubiquitin; C508130:Whi5 protein, S cerevisiae; C471606:RAD6 protein, S cerevisiae; D044763:Ubiquitin-Conjugating Enzymes; D017489:CDC28 Protein Kinase, S cerevisiae