The Schizosaccharomyces pombe MBF complex requires heterodimerization for entry into S phase.
In Schizosaccharomyces pombe, MBF is a DNA-binding complex suspected to activate the transcription of genes necessary for entry into S phase. The MBF complex contains both p85cdc10 and p72res1/sct1. To obtain a better understanding of how the MBF complex regulates gene expression at the G1/S transition, we have performed a genetic analysis of p72res1. We determined that p72res1 can bind specifically to the cdc22 promoter, when analyzed by gel mobility shift assay, and that the N-terminal 157 amino acids of p72res1 are sufficient for this specific binding. When overexpressed in vivo, a fragment of p72res1 containing this DNA-binding domain could rescue a strain carrying a temperature-sensitive cdc10 allele at the restrictive temperature as well as a strain with a cdc10 null allele. We also determined that the C-terminal region of p72res1 is necessary and sufficient for binding to p85cdc10. Overexpression of the cdc10-binding domain of p72res1 leads to a G1 arrest with a cdc phenotype and a decrease on MBF activity. Overexpression of full-length p72res1 also leads to a growth arrest that can be rescued by overexpression of p85cdc10. These results imply that the MBF activity in vivo is dependent on the interaction of p85cdc10 with p72res1.
Ayté
J
J
Division of Neoplastic Disease Mechanisms, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Leis
J F
JF
Herrera
A
A
Tang
E
E
Yang
H
H
DeCaprio
J A
JA
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D016196:S Phase; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D017384:Sequence Deletion; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D018797:Cell Cycle Proteins; D017931:DNA Primers; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C061178:cdc10 protein, S pombe; C078732:res1 protein, S pombe