Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Swi4-dependent SWI4 transcription couples cell size to cell cycle commitment

ABSTRACT: Growth-dependent accumulation of the limiting SBF transcription factor, composed of Swi4 and Swi6, occurs in G1 phase in budding yeast and is limiting for commitment to division, termed Start. Here we measure size-dependence of Swi4 protein copy number under different genetic contexts using a quantitative scanning number and brightness technique. Mutation of SBF binding sites in the SWI4 promoter or disruption of SBF activation resulted in ~33-50% decrease in Swi4 accumulation rate and concordantly increased cell size at Start. Ectopic inducible expression of Swi4 in G1 phase cells increased production of Swi4 from the endogenous promoter, upregulated transcription of the G1/S regulon, and accelerated Start. Despite the potential for Swi4 positive feedback, G1 phase Swi4 accumulation was linear unless the Whi5 transcriptional repressor was inactivated. A threshold model in which Swi4 titrates SBF binding sites in G1/S promoters predicted the effects of nutrients, ploidy, and G1/S regulatory mutations on cell size. These results exemplify how transcription factor auto-production can refine a cell state transition.

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE279708 | GEO | 2025/02/14

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

NRS1, a nitrogen source-regulated microprotein, confers an alternative mechanism of G1/S transcriptional activation in budding yeast

Project description:Commitment to cell division at the end of G1 phase, termed Start in the budding yeast Saccharomyces cerevisiae, is strongly influenced by nutrient availability. To identify newdominant activators of Start that might operate under different nutrient conditions, we screened a genome-wide ORF overexpression library for genes that bypass a Start arrest caused by absence of the G1 cyclin Cln3 and the transcriptional activator Bck2. We recovered a hypothetical gene YLR053c, renamed NRS1 for Nitrogen-responsive Start Regulator 1, which encodes a poorly characterized 108 amino acid microprotein. Endogenous NRS1 was nuclear-localized, restricted to poor nitrogen conditions, induced upon mTORC1 inhibition, and cell cycle-regulated with a peak at Start. NRS1 interacted genetically with SWI4 and SWI6, which encode the master G1/S transcription factor complex SBF. Correspondingly, NRS1 physically interacted with Swi4 and Swi6 and was localized to G1/S promoter DNA. NRS1 exhibited inherent transactivation activity and fusion of NRS1 to the SBF inhibitor Whi5 was sufficient to suppress other Start defects. NRS1 appears to be a recently evolved microprotein that rewires the G1/S transcriptional machinery under poor nutrient conditions.

2021-08-25 | PXD018681 | Pride

A nitrogen source-regulated microprotein confers an alternative mechanism of G1/S transcriptional activation in budding yeast

Project description:Commitment to cell division at the end of G1 phase, termed Start in the budding yeast Saccharomyces cerevisiae, is strongly influenced by nutrient availability. To identify new dominant activators of Start that might operate under different nutrient conditions, we screened a genome-wide ORF overexpression library for genes that bypass a Start arrest caused by absence of the G1 cyclin Cln3 and the transcriptional activator Bck2. We recovered a hypothetical gene YLR053c, renamed NRS1 for Nitrogen-Responsive Start regulator 1, which encodes a poorly characterized 108 amino acid microprotein. Endogenous Nrs1 was nuclear-localized, restricted to poor nitrogen conditions, induced upon mTORC1 inhibition, and cell cycle-regulated with a peak at Start. NRS1 interacted genetically with SWI4 and SWI6, which encode subunits of the main G1/S transcription factor complex SBF. Correspondingly, Nrs1 physically interacted with Swi4 and Swi6 and was localized to G1/S promoter DNA. Nrs1 exhibited inherent transactivation activity and fusion of Nrs1 to the SBF inhibitor Whi5 was sufficient to suppress other Start defects. Nrs1 appears to be a recently evolved microprotein that rewires the G1/S transcriptional machinery under poor nutrient conditions.

2021-08-25 | GSE179366 | GEO

LUTI-dependent Downregulation of a Cell Cycle Transcription Factor is Key for Timely Meiotic Entry

Project description:We used RNA-seq to monitor expression of early meiotic genes and expression of mitotic transcription factor SBF targets. Increased SBF activity was achieved through either overexpression of SBF unique subunit Swi4 , removal of LUTI-mediated regulation of Swi4 levels, or nuclear depeletion of negative regulator of SBF Whi5.

2023-12-05 | GSE225963 | GEO

Role of a Candida albicans Whi5/Nrm1 homolog in cell cycle and hyphal-specific gene expression

Project description:Candida albicans is an opportunistic pathogenic fungus that is able to assume several morphologies, including yeast and hyphal growth forms. The hyphal morphology can be induced by various environmental stimuli and is accompanied by expression of a large set of hyphal-specific genes (HSGs). Cell cycle and morphogenetic programs are interconnected: notably, inhibition of cell cycle progression often causes a switch to filamentous growth. Here we identify and characterize CaNrm1, a C. albicans homolog of the S. cerevisiae Whi5 and Nrm1 transcription inhibitors that, analogous to mammalian Rb, regulate the cell cycle transcription program in the G1 phase and at the G1/S transition. CaNRM1 is able to complement the phenotypes of both whi5 and nrm1 mutants in S. cerevisiae. Deletion of CaNRM1 causes a reduction in cell size and results in increased resistance to hydroxyurea (HU), an inhibitor of DNA replication; analysis of the expression of ribonucleotide reductase, the target of HU, suggests that its transcriptional induction in response to HU is mainly dependent upon CaNrm1. Genetic epistasis analysis suggests that CaNrm1 interacts with the SBF and MBF transcription factors in S. cerevisiae and with the MBF functional homolog in C. albicans. At the transcription level, deletion of CaNRM1 causes an induction of many G1 and G1/S-specific genes. Induction of the HSGs is dampened under certain conditions in the Canrm1-/- mutant, suggesting that the cell cycle transcription program influences the morphogenetic transcription program of C. albicans. One aspect of the characterization of the C. albicans Whi5/Nrm1 gene was to examine how this molecule influences global gene expression. To that end, we isolated total RNA from log-phase nrm1-/nrm1- (as well as parent/background strain) cells in two independent replicate experiments. These samples were processed, labeled, and subsequently used for hybridization of custom C. albicans Affymetrix arrays.

2012-01-01 | E-GEOD-20612 | biostudies-arrayexpress

Localized phosphorylation of RNA Polymerase II by G1 cyclin-Cdk promotes cell cycle entry

Project description:The cell cycle is thought to be initiated by cyclin-dependent kinases (Cdk) inactivating transcriptional inhibitors of cell cycle gene-expression. In budding yeast, the G1 cyclin Cln3-Cdk1 complex is thought to directly phosphorylate Whi5, thereby releasing the transcription factor SBF and committing cells to division. Here, we report that Cln3-Cdk1 does not phosphorylate Whi5, but instead phosphorylates the RNA Polymerase II subunit Rpb1’s C-terminal domain (CTD) on S5 of its heptapeptide repeats. Cln3-Cdk1 binds SBF-regulated promoters(8) and Cln3’s function can be performed by the canonical S5 kinase Ccl1-Kin28 when synthetically recruited to SBF. Thus, Cln3-Cdk1 triggers cell division by phosphorylating Rpb1 at SBF-regulated promoters to promote transcription. Our findings blur the distinction between cell cycle and transcriptional Cdks to highlight the ancient relationship between these processes.

2021-12-01 | GSE169271 | GEO

Budding yeast size control by titration of nuclear sites

Project description:This model is decribed in the article: Dilution and titration of cell-cycle regulators may control cell size in budding yeast Frank S. Heldt, Reece Lunstone, John J. Tyson, Bela Novak PLoS Comput Biol, October 2018, 14(10), e1006548, doi: 10.1371/journal.pcbi.1006548 Abstract: The size of a cell sets the scale for all biochemical processes within it, thereby affecting cellular fitness and survival. Hence, cell size needs to be kept within certain limits and relatively constant over multiple generations. However, how cells measure their size and use this information to regulate growth and division remains controversial. Here, we present two mechanistic mathematical models of the budding yeast (S. cerevisiae) cell cycle to investigate competing hypotheses on size control: inhibitor dilution and titration of nuclear sites. Our results suggest that an inhibitor-dilution mechanism, in which cell growth dilutes the transcriptional inhibitor Whi5 against the constant activator Cln3, can facilitate size homeostasis. This is achieved by utilising a positive feedback loop to establish a fixed size threshold for the START transition, which efficiently couples cell growth to cell cycle progression. Yet, we show that inhibitor dilution cannot reproduce the size of mutants that alter the cell’s overall ploidy and WHI5 gene copy number. By contrast, size control through titration of Cln3 against a constant number of genomic binding sites for the transcription factor SBF recapitulates both size homeostasis and the size of these mutant strains. Moreover, this model produces an imperfect ‘sizer’ behaviour in G1 and a ‘timer’ in S/G2/M, which combine to yield an ‘adder’ over the whole cell cycle; an observation recently made in experiments. Hence, our model connects these phenomenological data with the molecular details of the cell cycle, providing a systems-level perspective of budding yeast size control.

2024-09-02 | BIOMD0000000856 | BioModels

Heldt2018 - Budding yeast size control by titration of nuclear sites

2019-01-09 | MODEL1803220002 | BioModels

Role of a Candida albicans Whi5/Nrm1 homolog in cell cycle and hyphal-specific gene expression

2012-01-01 | GSE20612 | GEO

Dot6 is a major regulator of cell size and a transcriptional activator of ribosome biogenesis in the opportunistic yeast Candida albicans

Project description:In most species, size homeostasis appears to be exerted in late G1 phase as cells commit to division, called Start in yeast and the Restriction Point in metazoans. This size threshold couples cell growth to division and thereby establishes long-term size homeostasis. Our former investigations have shown that hundreds of genes markedly altered cell size under homeostatic growth conditions in the opportunistic yeast Candida albicans, but surprisingly only few of these overlapped with size control genes in the budding yeast Saccharomyces cerevisiae. Here, we investigated one of the divergent potent size regulators in C. albicans, the Myb-like HTH transcription factor Dot6. Our data demonstrated that Dot6 is a negative regulator of Start and also acts as a transcriptional activator of ribosome biogenesis (Ribi) genes. Genetic epistasis uncovered that Dot6 interacted with the master transcriptional regulator of the G1 machinery, SBF complex, but not with the Ribi and cell size regulators Sch9, Sfp1 and p38/Hog1. Dot6 was required for carbon-source modulation of cell size and it is regulated at the level of nuclear localization by TOR pathway. Our findings support a model where Dot6 acts as a hub that integrate directly growth cues via the TOR pathway to control the commitment to mitotic division at G1.

2018-08-28 | GSE119089 | GEO

Transcriptional and chromatin-based partitioning mechanisms uncouple protein scaling from cell size

Project description:Biosynthesis scales with cell size such that protein concentrations generally remain constant as cells grow. As an exception, synthesis of the cell-cycle inhibitor Whi5 ‘sub-scales’ with cell size so that its concentration is lower in larger cells to promote cell-cycle entry. Here, we find that a transcriptional control uncouples Whi5 synthesis from cell size and, screening for similar genes, identify histones as the major class of sub-scaling transcripts besides WHI5. Histone synthesis is thereby matched to genome content rather than cell size. Such sub-scaling proteins are challenged by asymmetric cell division because proteins are typically partitioned in proportion to new-born cell volume. To avoid this fate, Whi5 uses chromatin-binding to partition similar protein amounts to each new-born cell regardless of cell size. Finally, disrupting both Whi5 synthesis and chromatin-based partitioning compromises G1 size control. Thus, specific transcriptional and partitioning mechanisms determine protein sub-scaling to control cell size.

2021-12-01 | GSE167842 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data