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Gene Review

MBP1  -  Mbp1p

Saccharomyces cerevisiae S288c

Synonyms: MBF subunit p120, Transcription factor MBP1, YDL056W
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Disease relevance of MBP1


High impact information on MBP1

  • The related Swi4 and Mbp1 proteins are the DNA-binding components of the respective factors, and Swi6 mayhave a regulatory function [2].
  • Strains deleted for both MBP1 and SWI4 were inviable, demonstrating that transcriptional activation by MBF and SBF has an important role in the transition from G1 to S phase [3].
  • In contrast, other known Start regulators Mbp1 and Cln3 are not needed for coherence but ensure regular timing of Start onset [4].
  • When fused to the LexA DNA-binding domain, Xbp1 acts as transcriptional repressor, defining it as the first repressor in the Swi4/Mbp1 family and the first potential negative regulator of transcription induced by stress [5].
  • Similarly, high overexpression of Mbp1 is lethal and can be suppressed by skn7 mutations [6].

Biological context of MBP1

  • We further demonstrate that during meiosis MCBs function as effective transcriptional activators independent of MBP1 [7].
  • Association of the cell cycle transcription factor Mbp1 with the Skn7 response regulator in budding yeast [6].
  • Pct1+ is related to, but distinct from, the res1+/sct1+ gene that also encodes a p85cdc10 partner. p73pct1 has centrally located ankyrin repeats and a putative amino-terminal DNA-binding domain that has extensive sequence similarity to the DNA-binding domains of the Saccharomyces cerevisiae SWI4 and MBP1 proteins [8].
  • In proliferating S. cerevisiae, genes whose products function in DNA replication are regulated by the MBF transcription factor composed of Mbp1 and Swi6 that binds to consensus MCB sequences in target promoters [7].
  • Changes in the backbone amide proton and nitrogen chemical shifts upon DNA binding have enabled us to experimentally define a DNA-binding surface on the core N-terminal domain of Mbp1 that is associated with a putative winged helix-turn-helix motif [9].

Anatomical context of MBP1

  • The HeLa cDNA sequence is highly similar to MBP1 and it encodes peptides obtained directly from human erythrocyte S5a [10].
  • Based upon the MBP1 cDNA sequence we have now isolated a HeLa cell cDNA coding for human S5a [10].
  • CONCLUSIONS: Despite little sequence similarity, the structure within the core region of the Mbp1 N-terminal domain exhibits a similar fold to that of the DNA-binding domains of other proteins, such as hepatocyte nuclear factor-3gamma and histone H5 from eukaryotes, and the prokaryotic catabolite gene activator [11].

Associations of MBP1 with chemical compounds

  • The response to glucose is partially suppressed by inactivation of SWI4, but not MBP1, which is consistent with the dependence of MCB core elements upon the SCB-binding transcription factor (SBF) [12].
  • However, alanine substitution of two lysine residues (116 and 122) within the C-terminal extension (tail) of Mbp1 considerably reduces the apparent affinity for an MCB (MluI cell-cycle box) containing oligonucleotide [9].

Other interactions of MBP1

  • Furthermore, elevated MBP1, a transcriptional regulator of cyclins, altered the transcriptional start site in CLN3 mRNA, shifting it 45 nucleotides upstream of the normal [13].
  • Surprisingly, deletion of MBP1 had no effect on the meiotic expression of CLB5, which is purportedly controlled by MBF [7].
  • MBF is composed of Mbp1 and Swi6 and activates the transcription of genes required for DNA synthesis [14].
  • On the contrary, loss of MSN5 has no effect on the closely related transcription factor MBF (composed of the Mbp1p and Swi6p proteins) [15].
  • For most G1/S-regulated genes that we tested in a cdc20 block-release protocol for cell-cycle synchronization, removal of both Swi4 and Mbp1 was necessary and sufficient to essentially eliminate cell-cycle-regulated expression [16].

Analytical, diagnostic and therapeutic context of MBP1



  1. Expression, purification, and crystallization of the DNA-binding domain from the Saccharomyces cerevisae cell-cycle transcription factor MBP-1. Taylor, I.A., Smerdon, S.J. Proteins (1997) [Pubmed]
  2. Genomic binding sites of the yeast cell-cycle transcription factors SBF and MBF. Iyer, V.R., Horak, C.E., Scafe, C.S., Botstein, D., Snyder, M., Brown, P.O. Nature (2001) [Pubmed]
  3. A role for the transcription factors Mbp1 and Swi4 in progression from G1 to S phase. Koch, C., Moll, T., Neuberg, M., Ahorn, H., Nasmyth, K. Science (1993) [Pubmed]
  4. Coherence and timing of cell cycle start examined at single-cell resolution. Bean, J.M., Siggia, E.D., Cross, F.R. Mol. Cell (2006) [Pubmed]
  5. Xbp1, a stress-induced transcriptional repressor of the Saccharomyces cerevisiae Swi4/Mbp1 family. Mai, B., Breeden, L. Mol. Cell. Biol. (1997) [Pubmed]
  6. Association of the cell cycle transcription factor Mbp1 with the Skn7 response regulator in budding yeast. Bouquin, N., Johnson, A.L., Morgan, B.A., Johnston, L.H. Mol. Biol. Cell (1999) [Pubmed]
  7. Meiosis-specific regulation of the Saccharomyces cerevisiae S-phase cyclin CLB5 is dependent on MluI cell cycle box (MCB) elements in its promoter but is independent of MCB-binding factor activity. Raithatha, S.A., Stuart, D.T. Genetics (2005) [Pubmed]
  8. pct1+, which encodes a new DNA-binding partner of p85cdc10, is required for meiosis in the fission yeast Schizosaccharomyces pombe. Zhu, Y., Takeda, T., Nasmyth, K., Jones, N. Genes Dev. (1994) [Pubmed]
  9. Characterization of the DNA-binding domains from the yeast cell-cycle transcription factors Mbp1 and Swi4. Taylor, I.A., McIntosh, P.B., Pala, P., Treiber, M.K., Howell, S., Lane, A.N., Smerdon, S.J. Biochemistry (2000) [Pubmed]
  10. Molecular cloning and expression of a multiubiquitin chain binding subunit of the human 26S protease. Ferrell, K., Deveraux, Q., van Nocker, S., Rechsteiner, M. FEBS Lett. (1996) [Pubmed]
  11. Crystal structure of the DNA-binding domain of Mbp1, a transcription factor important in cell-cycle control of DNA synthesis. Xu, R.M., Koch, C., Liu, Y., Horton, J.R., Knapp, D., Nasmyth, K., Cheng, X. Structure (1997) [Pubmed]
  12. 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]
  13. Overexpression of eIF4E in Saccharomyces cerevisiae causes slow growth and decreased alpha-factor response through alterations in CLN3 expression. Anthony, C., Zong, Q., De Benedetti, A. J. Biol. Chem. (2001) [Pubmed]
  14. Regulation of transcription at the Saccharomyces cerevisiae start transition by Stb1, a Swi6-binding protein. Ho, Y., Costanzo, M., Moore, L., Kobayashi, R., Andrews, B.J. Mol. Cell. Biol. (1999) [Pubmed]
  15. Cell cycle activation of the Swi6p transcription factor is linked to nucleocytoplasmic shuttling. Queralt, E., Igual, J.C. Mol. Cell. Biol. (2003) [Pubmed]
  16. High functional overlap between MluI cell-cycle box binding factor and Swi4/6 cell-cycle box binding factor in the G1/S transcriptional program in Saccharomyces cerevisiae. Bean, J.M., Siggia, E.D., Cross, F.R. Genetics (2005) [Pubmed]
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