title: The yeast PUF protein Puf5 has Pop2-independent roles in response to DNA replication stress.
abstract: PUFs are RNA binding proteins that promote mRNA deadenylation and decay and inhibit translation. Yeast Puf5 is the prototype for studying PUF-dependent gene repression. Puf5 binds to the Pop2 subunit of the Ccr4-Pop2-NOT mRNA deadenylase, recruiting the deadenylase and associated translational repressors to mRNAs. Here we used yeast genetics to show that Puf5 has additional roles in vivo that do not require Pop2. Deletion of PUF5 caused increased sensitivity to DNA replication stress in cells lacking Pop2, as well as in cells mutated for two activities recruited to mRNAs by the Puf5-Pop2 interaction, the deadenylase Ccr4 and the translational repressor Dhh1. A functional Puf5 RNA binding domain was required, and Puf5 cytoplasmic localisation was sufficient for resistance to replication stress, indicating posttranscriptional gene expression control is involved. In contrast to DNA replication stress, in response to the cell wall integrity pathway activator caffeine, PUF5 and POP2 acted in the same genetic pathway, indicating that functions of Puf5 in the caffeine response are mediated by Pop2-dependent gene repression. Our results support a model in which Puf5 uses multiple, Pop2-dependent and Pop2-independent mechanisms to control mRNA expression. The Pop2-independent roles for Puf5 could involve spatial control of gene expression, a proposition supported by our data indicating that the active form of Puf5 is localised to cytoplasmic foci.
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia. ana.traven@med.monash.edu.au
authors.forename: Ana
authors.initials: A
authors.lastname: Traven
authors.forename: Tricia L
authors.initials: TL
authors.lastname: Lo
authors.forename: Trevor
authors.initials: T
authors.lastname: Lithgow
authors.forename: Jörg
authors.initials: J
authors.lastname: Heierhorst
mesh_terms: D002110:Caffeine / Q000494:pharmacology; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects; D025141:Drug Resistance, Fungal / Q000187:drug effects; D006918:Hydroxyurea / Q000494:pharmacology; D009154:Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: C449502:MPT5 protein, S cerevisiae; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D002110:Caffeine; D012260:Ribonucleases; C079009:POP2 protein, S cerevisiae; D006918:Hydroxyurea