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Updated: May 24, 2026
08:13
Manipulation and Analysis of Cell Cycle-Dependent Processes in Budding Yeast
Published on: September 26, 2025
A synthetic human kinase can control cell cycle progression in budding yeast
Megan J Davey1, Heather J Andrighetti, Xiaoli Ma
1Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1.
G3 (Bethesda, Md.)
|March 3, 2012
Summary
Human and yeast DDK kinase complexes show species-specific interactions. While human DDK can substitute for yeast DDK in basic cell growth, it fails in more complex functions like DNA repair and sporulation, indicating conserved substrate targeting but distinct protein interactions.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- The DDK (D Cdc7-Dbf4) kinase complex is crucial for S-phase progression in eukaryotes.
- Sequence conservation varies between human and yeast DDK subunits, suggesting potential functional differences.
Purpose of the Study:
- To investigate the functional conservation and species-specific interactions of the human DDK complex in Saccharomyces cerevisiae.
- To identify the regions of Cdc7 responsible for species-specific DDK function.
Main Methods:
- Complementation assays using human CDC7 and DBF4 in yeast deletion strains (cdc7Δ, dbf4Δ).
- Flow cytometry to assess cell cycle progression.
- Hydroxyurea sensitivity and sporulation assays to evaluate DDK function.
- Site-directed mutagenesis to create a hybrid human-yeast Cdc7 protein.
Main Results:
- Human DDK (hDDK) complements yeast growth defects in cdc7Δ and dbf4Δ strains, with HsDbf4 identified as the functional ortholog of ScDbf4.
- Yeast expressing hDDK exhibit normal cell cycle progression but show sensitivity to hydroxyurea and impaired sporulation.
- A hybrid Cdc7 protein with the C-terminal 55 amino acids from yeast restored hydroxyurea resistance and sporulation, indicating this region is critical for species-specific function.
Conclusions:
- Human DDK can substitute for essential functions of yeast DDK, but not all, highlighting species-specific functional divergence.
- The C-terminus of Cdc7 is a key determinant of DDK species-specific interactions and functions.
- While substrate targeting by DDK is conserved, the complex's internal interactions and regulation show species specificity.
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