Recovery of the Yeast Cell Cycle from Heat Shock-induced G1 Arrest Involves a Positive Regulation of G1Cyclin Expression by the S Phase Cyclin Clb5*

In the yeast Saccharomyces cerevisiae, heat shock stress induces a variety of cellular responses including a transient cell cycle arrest before G1/S transition. Previous studies have suggested that this G1 delay is probably attributable to a reduced level of the G1 cyclin gene (CLN1 and CLN2) transcripts. Here we report our finding that the G1 cyclin Cln3 and the S cyclin Clb5 are the key factors required for recovery from heat shock-induced G1 arrest. Heat shock treatment of G1 cells lacking either CLN3 orCLB5/CLB6 functions leads to prolonged cell cycle arrest before the initiation of DNA synthesis, concomitant with a severe deficiency in bud formation. The inability of the clb5 clb6 mutant to resume normal budding after heat shock treatment is unanticipated, since the S phase cyclins are generally thought to be required mainly for initiation of DNA synthesis and have no significant roles in bud formation in the presence of functional G1cyclins. Further studies reveal that the accumulation of G1cyclin transcripts is markedly delayed in the clb5 clb6mutant following heat shock treatment, indicating that theCLN gene expression may require Clb5/Clb6 to attain a threshold level for driving the cell cycle through G1/S transition. Consistent with this assumption, overproduction of Clb5 greatly enhances the transcription of at least two G1cyclin genes (CLN1 and CLN2) in heat-shocked G1 cells. These results suggest that Clb5 may positively regulate the expression of G1 cyclins during cellular recovery from heat shock-induced G1 arrest. Additional evidence is presented to support a role for Clb5 in maintaining the synchrony between budding and DNA synthesis during normal cell division as well.

[1]  M. Mendenhall,et al.  Regulation of Cdc28 Cyclin-Dependent Protein Kinase Activity during the Cell Cycle of the Yeast Saccharomyces cerevisiae , 1998, Microbiology and Molecular Biology Reviews.

[2]  A. Toh-E,et al.  Phosphorylation of sic1, a cyclin-dependent kinase (Cdk) inhibitor, by Cdk including Pho85 kinase is required for its prompt degradation. , 1998, Molecular biology of the cell.

[3]  D. Hall,et al.  Regulation of the Cln3–Cdc28 kinase by cAMP in Saccharomyces cerevisiae , 1998, The EMBO journal.

[4]  A. Reindl,et al.  Regulation of the heat-shock response. , 1998, Plant physiology.

[5]  F. Cross,et al.  Cyclin-specific START events and the G1-phase specificity of arrest by mating factor in budding yeast , 1998, Molecular and General Genetics MGG.

[6]  Paul V. Attfield,et al.  Stress tolerance: The key to effective strains of industrial baker's yeast , 1997, Nature Biotechnology.

[7]  L. Breeden,et al.  Xbp1, a stress-induced transcriptional repressor of the Saccharomyces cerevisiae Swi4/Mbp1 family , 1997, Molecular and cellular biology.

[8]  S. Carr,et al.  Phosphorylation of Sic1p by G1 Cdk required for its degradation and entry into S phase. , 1997, Science.

[9]  R. Deshaies,et al.  A Complex of Cdc4p, Skp1p, and Cdc53p/Cullin Catalyzes Ubiquitination of the Phosphorylated CDK Inhibitor Sic1p , 1997, Cell.

[10]  R. Deshaies,et al.  SIC1 is ubiquitinated in vitro by a pathway that requires CDC4, CDC34, and cyclin/CDK activities. , 1997, Molecular biology of the cell.

[11]  X. Li,et al.  Inactivation of the cyclin-dependent kinase Cdc28 abrogates cell cycle arrest induced by DNA damage and disassembly of mitotic spindles in Saccharomyces cerevisiae , 1997, Molecular and cellular biology.

[12]  B. Futcher,et al.  Cyclins and the Wiring of the Yeast Cell Cycle , 1996, Yeast.

[13]  K. Nasmyth.  At the heart of the budding yeast cell cycle. , 1996, Trends in genetics : TIG.

[14]  M. Tyers,et al.  The cyclin-dependent kinase inhibitor p40SIC1 imposes the requirement for Cln G1 cyclin function at Start. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[15]  T. Böhm,et al.  Activation of S-phase-promoting CDKs in late G1 defines a "point of no return" after which Cdc6 synthesis cannot promote DNA replication in yeast. , 1996, Genes & development.

[16]  A. Futcher,et al.  Linkage of Replication to Start by the Cdk Inhibitor Sic1 , 1996, Science.

[17]  L. Johnston,et al.  Rme1, a negative regulator of meiosis, is also a positive activator of G1 cyclin gene expression. , 1995, The EMBO journal.

[18]  C. Wittenberg,et al.  CLN3, not positive feedback, determines the timing of CLN2 transcription in cycling cells. , 1995, Genes & development.

[19]  L. Johnston,et al.  A yeast transcription factor bypassing the requirement for SBF and DSC1/MBF in budding yeast has homology to bacterial signal transduction proteins. , 1995, The EMBO journal.

[20]  L. Dirick,et al.  Roles and regulation of Cln‐Cdc28 kinases at the start of the cell cycle of Saccharomyces cerevisiae. , 1995, The EMBO journal.

[21]  K. Arndt,et al.  Activation of CLN1 and CLN2 G1 cyclin gene expression by BCK2 , 1995, Molecular and cellular biology.

[22]  L. Hartwell,et al.  Cell cycle control and cancer. , 1994, Science.

[23]  Susan Lindquist,et al.  Protein disaggregation mediated by heat-shock protein Hspl04 , 1994, Nature.

[24]  Kim Nasmyth,et al.  The B-type cyclin kinase inhibitor p40 SIC1 controls the G1 to S transition in S. cerevisiae , 1994, Cell.

[25]  E. Friedberg,et al.  Characterization of G1 checkpoint control in the yeast Saccharomyces cerevisiae following exposure to DNA-damaging agents. , 1994, Genetics.

[26]  K. Nasmyth,et al.  A role for the transcription factors Mbp1 and Swi4 in progression from G1 to S phase. , 1993, Science.

[27]  K Nasmyth,et al.  CLB5 and CLB6, a new pair of B cyclins involved in DNA replication in Saccharomyces cerevisiae. , 1993, Genes & development.

[28]  B. Futcher,et al.  Comparison of the Saccharomyces cerevisiae G1 cyclins: Cln3 may be an upstream activator of Cln1, Cln2 and other cyclins. , 1993, The EMBO journal.

[29]  G C Johnston,et al.  Heat shock-mediated cell cycle blockage and G1 cyclin expression in the yeast Saccharomyces cerevisiae , 1993, Molecular and cellular biology.

[30]  F. Hartl,et al.  Molecular chaperone functions of heat-shock proteins. , 1993, Annual review of biochemistry.

[31]  S. Lindquist,et al.  The function of heat-shock proteins in stress tolerance: degradation and reactivation of damaged proteins. , 1993, Annual review of genetics.

[32]  K. Arndt,et al.  SIT4 protein phosphatase is required for the normal accumulation of SWI4, CLN1, CLN2, and HCS26 RNAs during late G1. , 1992, Genes & development.

[33]  S. Reed,et al.  Cyclin-B homologs in Saccharomyces cerevisiae function in S phase and in G2. , 1992, Genes & development.

[34]  F. Cross,et al.  CLB5: a novel B cyclin from budding yeast with a role in S phase. , 1992, Genes & development.

[35]  K Nasmyth,et al.  Characterization of four B-type cyclin genes of the budding yeast Saccharomyces cerevisiae. , 1992, Molecular biology of the cell.

[36]  S. Lindquist.  Heat-shock proteins and stress tolerance in microorganisms. , 1992 .

[37]  Kim Nasmyth,et al.  The role of SWI4 and SWI6 in the activity of G1 cyclins in yeast , 1991, Cell.

[38]  F. Cross,et al.  A potential positive feedback loop controlling CLN1 and CLN2 gene expression at the start of the yeast cell cycle , 1991, Cell.

[39]  K Nasmyth,et al.  A general approach to the isolation of cell cycle-regulated genes in the budding yeast, Saccharomyces cerevisiae. , 1991, Journal of molecular biology.

[40]  E. Craig,et al.  Structure and regulation of the SSA4 HSP70 gene of Saccharomyces cerevisiae. , 1990, The Journal of biological chemistry.

[41]  Fred Winston,et al.  Methods in Yeast Genetics: A Laboratory Course Manual , 1990 .

[42]  G. C. Johnston,et al.  Thermotolerance is independent of induction of the full spectrum of heat shock proteins and of cell cycle blockage in the yeast Saccharomyces cerevisiae , 1990, Journal of bacteriology.

[43]  Curt Wittenberg,et al.  G1-specific cyclins of S. cerevisiae: Cell cycle periodicity, regulation by mating pheromone, and association with the p34 CDC28 protein kinase , 1990, Cell.

[44]  L. Hartwell,et al.  Checkpoints: controls that ensure the order of cell cycle events. , 1989, Science.

[45]  K. Matsumoto,et al.  Heat shock response of Saccharomyces cerevisiae mutants altered in cyclic AMP-dependent protein phosphorylation , 1987, Molecular and cellular biology.

[46]  Gerald R. Fink,et al.  Methods in Yeast Genetics: A Laboratory Course Manual , 1987 .

[47]  S. Lindquist.  The heat-shock response. , 1986, Annual review of biochemistry.

[48]  J. Sambrook,et al.  Molecular Cloning: A Laboratory Manual , 2001 .

[49]  D. Finkelstein,et al.  Alterations of transcription during heat shock of Saccharomyces cerevisiae. , 1982, The Journal of biological chemistry.

[50]  G. Fink,et al.  Methods in yeast genetics , 1979 .