title: Antagonistic gene transcripts regulate adaptation to new growth environments.
abstract: Cells have evolved complex regulatory networks that reorganize gene expression patterns in response to changing environmental conditions. These changes often involve redundant mechanisms that affect various levels of gene expression. Here, we examine the consequences of enhanced mRNA degradation in the galactose utilization network of Saccharomyces cerevisiae. We observe that glucose-induced degradation of GAL1 transcripts provides a transient growth advantage to cells upon addition of glucose. We show that the advantage arises from relief of translational competition between GAL1 transcripts and those of cyclin CLN3, a translationally regulated initiator of cell division. This competition creates a translational bottleneck that balances the production of Gal1p and Cln3p and represents a posttranscriptional control mechanism that enhances the cell's ability to adapt to changes in carbon source. We present evidence that the spatial regulation of GAL1 and CLN3 transcripts is what allows growth to be maintained during fluctuations of glucose availability. Our results provide unique insights into how cells optimize energy use during growth in a dynamic environment.
authors.affiliation: Department of Bioengineering, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Bridget L
authors.initials: BL
authors.lastname: Baumgartner
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Bennett
authors.forename: Michael
authors.initials: M
authors.lastname: Ferry
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Johnson
authors.forename: Lev S
authors.initials: LS
authors.lastname: Tsimring
authors.forename: Jeff
authors.initials: J
authors.lastname: Hasty
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics / Q000502:physiology*; D016213:Cyclins / Q000378:metabolism; D005686:Galactokinase / Q000378:metabolism*; D005690:Galactose / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000235:genetics / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D046210:Microfluidic Analytical Techniques; D012333:RNA, Messenger / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: C079895:CLN3 protein, S cerevisiae; D016213:Cyclins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C524219:GAL1 protein, S cerevisiae; D005686:Galactokinase; D005947:Glucose; D005690:Galactose