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Gene Review

CLN1  -  Cln1p

Saccharomyces cerevisiae S288c

Synonyms: G1/S-specific cyclin CLN1, YM9646.13, YMR199W
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High impact information on CLN1

  • All three events depend on activation of Cdc28 protein kinase by the G1 cyclins Cln1, -2, and -3 [1].
  • In daughter cells, transcription of CLN1 and CLN2 is induced in a size-dependent manner, and these cyclins are necessary for the normal timing of cell cycle initiation [2].
  • However, GPA1Val50 cells do not recover from division arrest in the absence of both CLN1 and CLN3, which encode G1 cyclins, indicating that the recovery-promoting activity of GPA1Val50 requires the function of G1 cyclins [3].
  • Using strains where CLN1 was expressed conditionally, the essential function of Cln proteins was found to be limited to the G1 phase [4].
  • In a/alpha diploid cells lacking CLN1 and CLN2, HCS26 is required for passage through G1 [5].

Biological context of CLN1


Anatomical context of CLN1


Associations of CLN1 with chemical compounds

  • Consistent with this, release from pheromone arrest (where CLN1 and CLN2 are not expressed) in cycloheximide shows no induction at all [10].
  • Because the Cln1 protein was previously shown to be elevated in grr1 mutants, the effect of CLN1 overexpression on sulfite sensitivity was investigated [11].
  • The SIT4 gene, which encodes a serine/threonine protein phosphatase, is required for the normal accumulation of CLN1, CLN2, and HCS26 RNAs during late G1 [12].
  • Regulation of cell size by glucose is exerted via repression of the CLN1 promoter [13].

Regulatory relationships of CLN1

  • Cln3 is believed to activate Cln1 and Cln2, which can then stimulate their own accumulation by means of a positive feedback loop [14].

Other interactions of CLN1

  • We find that stimulation of the Ras/cAMP pathway represses expression of CLN1, CLN2 and co-regulated genes, inhibiting Start [15].
  • In similar experiments, CLN1 is less efficient than CLN3 at activating Start [16].
  • Consistent with this assumption, overproduction of Clb5 greatly enhances the transcription of at least two G(1) cyclin genes (CLN1 and CLN2) in heat-shocked G(1) cells [17].
  • We identified RNR1, which encodes a subunit of ribonucleotide reductase, as a high-copy suppressor of the lethality of mec1 GAL1-CLN1 [18].
  • CLN1 overexpression had a similar effect when the FAR1 gene, encoding a negative regulator of CLN1/2 function, was deleted [6].


  1. The B-type cyclin kinase inhibitor p40SIC1 controls the G1 to S transition in S. cerevisiae. Schwob, E., Böhm, T., Mendenhall, M.D., Nasmyth, K. Cell (1994) [Pubmed]
  2. Different G1 cyclins control the timing of cell cycle commitment in mother and daughter cells of the budding yeast S. cerevisiae. Lew, D.J., Marini, N.J., Reed, S.I. Cell (1992) [Pubmed]
  3. SGV1 encodes a CDC28/cdc2-related kinase required for a G alpha subunit-mediated adaptive response to pheromone in S. cerevisiae. Irie, K., Nomoto, S., Miyajima, I., Matsumoto, K. Cell (1991) [Pubmed]
  4. An essential G1 function for cyclin-like proteins in yeast. Richardson, H.E., Wittenberg, C., Cross, F., Reed, S.I. Cell (1989) [Pubmed]
  5. Cell cycle control by a complex of the cyclin HCS26 (PCL1) and the kinase PHO85. Espinoza, F.H., Ogas, J., Herskowitz, I., Morgan, D.O. Science (1994) [Pubmed]
  6. G1 cyclins CLN1 and CLN2 repress the mating factor response pathway at Start in the yeast cell cycle. Oehlen, L.J., Cross, F.R. Genes Dev. (1994) [Pubmed]
  7. Mutations in RAD27 define a potential link between G1 cyclins and DNA replication. Vallen, E.A., Cross, F.R. Mol. Cell. Biol. (1995) [Pubmed]
  8. A transcriptional autoregulatory loop for KIN28-CCL1 and SRB10-SRB11, each encoding RNA polymerase II CTD kinase-cyclin pair, stimulates the meiotic development of S. cerevisiae. Ohkuni, K., Yamashita, I. Yeast (2000) [Pubmed]
  9. Identification of Translational Regulation Target Genes during Filamentous Growth in Saccharomyces cerevisiae: Regulatory Role of Caf20 and Dhh1. Park, Y.U., Hur, H., Ka, M., Kim, J. Eukaryotic Cell (2006) [Pubmed]
  10. Direct induction of G1-specific transcripts following reactivation of the Cdc28 kinase in the absence of de novo protein synthesis. Marini, N.J., Reed, S.I. Genes Dev. (1992) [Pubmed]
  11. Multicopy FZF1 (SUL1) suppresses the sulfite sensitivity but not the glucose derepression or aberrant cell morphology of a grr1 mutant of Saccharomyces cerevisiae. Avram, D., Bakalinsky, A.T. Genetics (1996) [Pubmed]
  12. SIT4 protein phosphatase is required for the normal accumulation of SWI4, CLN1, CLN2, and HCS26 RNAs during late G1. Fernandez-Sarabia, M.J., Sutton, A., Zhong, T., Arndt, K.T. Genes Dev. (1992) [Pubmed]
  13. Regulation of cell size by glucose is exerted via repression of the CLN1 promoter. Flick, K., Chapman-Shimshoni, D., Stuart, D., Guaderrama, M., Wittenberg, C. Mol. Cell. Biol. (1998) [Pubmed]
  14. Yeast G1 cyclins CLN1 and CLN2 and a GAP-like protein have a role in bud formation. Cvrcková, F., Nasmyth, K. EMBO J. (1993) [Pubmed]
  15. Inhibition of G1 cyclin activity by the Ras/cAMP pathway in yeast. Tokiwa, G., Tyers, M., Volpe, T., Futcher, B. Nature (1994) [Pubmed]
  16. Comparison of the Saccharomyces cerevisiae G1 cyclins: Cln3 may be an upstream activator of Cln1, Cln2 and other cyclins. Tyers, M., Tokiwa, G., Futcher, B. EMBO J. (1993) [Pubmed]
  17. Recovery of the yeast cell cycle from heat shock-induced G(1) arrest involves a positive regulation of G(1) cyclin expression by the S phase cyclin Clb5. Li, X., Cai, M. J. Biol. Chem. (1999) [Pubmed]
  18. Interaction between the MEC1-dependent DNA synthesis checkpoint and G1 cyclin function in Saccharomyces cerevisiae. Vallen, E.A., Cross, F.R. Genetics (1999) [Pubmed]
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