title: Whi3, an S. cerevisiae RNA-binding protein, is a component of stress granules that regulates levels of its target mRNAs.
abstract: RNA binding proteins (RBPs) are vital to the regulation of mRNA transcripts, and can alter mRNA localization, degradation, translation, and storage. Whi3 was originally identified in a screen for small cell size mutants, and has since been characterized as an RBP. The identification of Whi3-interacting mRNAs involved in mediating cellular responses to stress suggested that Whi3 might be involved in stress-responsive RNA processing. We show that Whi3 localizes to stress granules in response to glucose deprivation or heat shock. The kinetics and pattern of Whi3 localization in response to a range of temperatures were subtly but distinctly different from those of known components of RNA processing granules. Deletion of Whi3 resulted in an increase in the relative abundance of Whi3 target RNAs, either in the presence or absence of heat shock. Increased levels of the CLN3 mRNA in whi3Δ cells may explain their decreased cell size. Another mRNA target of Whi3 encodes the zinc-responsive transcription factor Zap1, suggesting a role for Whi3 in response to zinc stress. Indeed, we found that whi3Δ cells have enhanced sensitivity to zinc toxicity. Together our results suggest an expanded model for Whi3 function: in addition to its role as a regulator of the cell cycle, Whi3 may have a role in stress-dependent RNA processing and responses to a variety of stress conditions.
authors.affiliation: Department of Biology, Stanford University, Stanford, California, United States of America.
authors.forename: Kristen J
authors.initials: KJ
authors.lastname: Holmes
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America ; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Klass
authors.affiliation: Department of Biology, Stanford University, Stanford, California, United States of America.
authors.forename: Evan L
authors.initials: EL
authors.lastname: Guiney
authors.affiliation: Department of Biology, Stanford University, Stanford, California, United States of America.
authors.forename: Martha S
authors.initials: MS
authors.lastname: Cyert
mesh_terms: D020816:Amino Acid Motifs; D002712:Chlorides / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005973:Glutamine; D018869:Heat-Shock Response / Q000187:drug effects; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects; D017967:Zinc Compounds / Q000494:pharmacology
chemical_list: D002712:Chlorides; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C440012:Whi3 protein, S cerevisiae; D017967:Zinc Compounds; D005973:Glutamine; C016837:zinc chloride; D005947:Glucose