Cell Cycle Regulation of a Novel DNA Binding Complex in Saccharomyces cerevisiae with E2F-like Properties

Vemu, Sheela; Reichel, Ronald

doi:10.1074/jbc.270.35.20724

Cited by 8 publications

(5 citation statements)

References 29 publications

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“…Indeed, it was previously shown that Clb2p degradation is essential for exit from mitosis (Surana et al ., 1993), and disappearance of Clb2p would be a good indication that sun4 Δ uth1 Δ cells finish their cell cycle normally. Proteins were extracted from the samples obtained after elutriation and probed with an anti‐Clb2p antibody as well as one against Swi6p, a constitutive transcriptional factor (Vemu and Reichel, 1995) which we used here as a loading control. In accordance with the results obtained with wild‐type strain (Schwob et al ., 1994; Schwab et al ., 1997), Clb2p, which was absent in the elutriated sun4 Δ uth1 Δ cells, appeared at 90 min when cells entered G 2 and peaked around 120 min, at the time most cells have undergone mitosis (Figure 7).…”

Section: Resultsmentioning

confidence: 99%

The ?SUN? family: yeastSUN4/SCW3 is involved in cell septation

Mouassite

Camougrand

Schwob

et al. 2000

Yeast

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SUN4 is the fourth member of the SUN gene family from S. cerevisiae, whose products display high homology in their 258 amino acid C‐terminal domain. SIM1, UTH1, NCA3 (the founding members) are involved in different cellular processes (DNA replication, ageing, mitochondrial biogenesis) and it is shown herein that SUN4 plays a role in the cell septation process. sun4Δ cells are larger than wild‐type and begin a new cell cycle before they have separated from their mother cell. This phenotype is more pronounced in sun4Δ cells also deleted for UTH1. FACS analysis shows apparent polyploidy which disappears when the cell cycle is arrested by mating factor or nocodazole, indicating that cell septation is delayed without modification of the doubling time. Elutriated sun4Δ uth1Δ daughter cells are born larger, and therefore enter S phase sooner than their wild‐type counterpart. S phase duration, as well as timing of Clb2 degradation, is normal, but cell septation is delayed. Sun4p/Scw3p was recently described as a cell wall protein (Cappellaro et al., 1998) and, consistent with this notion, electron micrographs of sun4Δ cells show defects in the final steps of cell wall septation. Our data suggest that Sun4p and Uth1p might contribute to the regulated process of cell wall morphogenesis and septation. Copyright © 2000 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

The ?SUN? family: yeastSUN4/SCW3 is involved in cell septation

Mouassite

Camougrand

Schwob

et al. 2000

Yeast

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“…The Cln3–Cdc28 kinase could serve a similar function to move cells through G 1 , the rate of this process determining G 1 length. Whether such a system exists in yeast remains to be seen; however, it is worth noting that an E2F‐like activity (termed SCELA) has been identified in yeast (Vemu and Reichel, 1995). As is the case with E2F, SCELA binds to elements that regulate the expression of the downstream cyclins, in this case CLN1 and CLN2 .…”

Section: Discussionmentioning

confidence: 99%

Regulation of the Cln3-Cdc28 kinase by cAMP in Saccharomyces cerevisiae

et al. 1998

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The yeast Saccharomyces cerevisiae grows at widely varying rates in different growth media. In order to maintain a relatively constant cell size, yeast cells must regulate the rate of progress through the cell cycle to match changes in growth rate, moving quickly through G 1 in rich medium, and slowly in poor medium. We have examined connections between nutrients, and the expression and activity of Cln3-Cdc28 kinase that regulates the G 1 -S boundary of the cell cycle in yeast, a point referred to as Start. We find that Cln3 protein levels are highest in glucose and lower in poorer carbon sources. This regulation involves both transcriptional and post-transcriptional control. Although the RascAMP pathway does not appear to affect CLN3 transcription, cAMP increases Cln3 protein levels and Cln3-Cdc28 kinase activity. This regulation requires untranslated regions of the CLN3 message, and can be explained by changes in protein synthesis rates caused by cAMP. A model for CLN3 regulation and function is presented in which CLN3 regulates G 1 length in response to nutrients.

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“…Band shift assays using purified proteins or in vitro translation products suggest that Swi4 and Mbp1 provide the primary DNA recognition function and that Swi6 enhances the affinity of the complex for its target (10, 12, 13). More recently, another complex that binds SCBs but does not contain Swi6 or Swi4 has been reported (14).…”

Section: Mlu1 Cell Cycle Boxes or Mcbsmentioning

confidence: 99%

Thioredoxin Reductase-dependent Inhibition of MCB Cell Cycle Box Activity in Saccharomyces cerevisiae

Machado¹,

Morgan²,

Merrill³

1997

Journal of Biological Chemistry

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Mlu1 cell cycle box (MCB) elements are found near the start site of yeast genes expressed at G 1 /S. Basal promoters dependent on the elements for upstream activating sequence activity are inactive in ⌬swi6 yeast. Yeast were screened for mutations that activated MCB reporter genes in the absence of Swi6. The mutations identified a single complementation group. Functional cloning revealed the mutations were alleles of the TRR1 gene encoding thioredoxin reductase. Although deletion of TRR1 activated MCB reporter genes, high copy expression did not suppress reporter gene activity. The trr1 mutations strongly (20-fold) stimulated MCB-and SCB (Swi4/Swi6 cell cycle box)-containing reporter genes, but also weakly (3-fold) stimulated reporter genes that lacked these elements. The trr1 mutations did not affect the level or periodicity of three endogenous MCB gene mRNAs (TMP1, RNR1, and SWI4). Deletion of thioredoxin genes TRX1 and TRX2 recapitulated the stimulatory effect of trr1 mutations on MCB reporter gene activity. Conditions expected to oxidize thioredoxin (exposure to H 2 O 2 ) induced MCB gene expression, whereas conditions expected to conserve thioredoxin (exposure to hydroxyurea) inhibited MCB gene expression. The results suggest that thioredoxin oxidation contributes to MCB element activation and suggest a link between thioredoxin-oxidizing processes such as ribonucleotide reduction and cell cycle-specific gene transcription.

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Cell Cycle Regulation of a Novel DNA Binding Complex in Saccharomyces cerevisiae with E2F-like Properties

Cited by 8 publications

References 29 publications

The ?SUN? family: yeastSUN4/SCW3 is involved in cell septation

The ?SUN? family: yeastSUN4/SCW3 is involved in cell septation

Regulation of the Cln3-Cdc28 kinase by cAMP in Saccharomyces cerevisiae

Thioredoxin Reductase-dependent Inhibition of MCB Cell Cycle Box Activity in Saccharomyces cerevisiae

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