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Updated: May 24, 2026

A Deep-sequencing-assisted, Spontaneous Suppressor Screen in the Fission Yeast Schizosaccharomyces pombe
Published on: March 7, 2019
Treslin, DUE-B, and GEMC1 cannot complement Sld3 mutants in fission yeast
Zhuo Wang1, Elaine Kim, Michael Leffak
1Department of Biochemistry and Molecular Biology, Wright State University Boonshoft School of Medicine, Dayton, OH 45435, USA.
Researchers investigated if metazoan proteins Treslin/Ticrr, GEMC1, and DUE-B could functionally replace yeast Sld3 in DNA replication. These proteins did not rescue growth defects in yeast mutants, suggesting evolutionary divergence in helicase activation mechanisms.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Eukaryotic DNA replication initiation involves prereplication complex formation and preinitiation complex assembly.
- In yeast, the Sld2-Dpb11-Sld3 complex is crucial for preinitiation complex assembly.
- Mammalian orthologs RecQL4 and TopBP1 are candidates for yeast Sld2 and Dpb11, respectively.
Purpose of the Study:
- To determine if metazoan proteins Treslin/Ticrr, GEMC1, and DUE-B function as Sld3 orthologs in eukaryotes.
- To investigate the evolutionary conservation of DNA replication initiation pathways.
Main Methods:
- Complementation tests were performed in fission yeast.
- Metazoan proteins were expressed in temperature-sensitive sld3-10 mutant yeast and cells lacking endogenous Sld3.
Main Results:
- None of the tested metazoan proteins (Treslin/Ticrr, GEMC1, DUE-B) could rescue the growth defect of sld3 yeast mutants.
- This indicates a lack of functional conservation for these specific proteins in the Sld3 role.
Conclusions:
- The tested metazoan proteins are not functional orthologs of yeast Sld3.
- Mammalian DNA helicase activation may have evolved greater complexity involving multiple TopBP1-interacting proteins.
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